- Phosphorylation of 2-azabicyclo[2.2.1]hept-5-ene and 2-hydroxy-2- azabicyclo[2.2.1]hept-5-ene systems: Synthesis and mechanistic study
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The endo and exo isomers of (±)-methyl 2-hydroxy-2-azabicyclo[2.2.1] hept-5-ene-3-carboxylates and the in situ-prepared endo and exo isomers of (±)-methyl 2-azabicyclo[2.2.1]hept-5-ene-3-carboxylate were treated with diphenylphosphinic chloride (OPClPh2) and chlorodiphenylphosphine (ClPPh2) to afford the corresponding phosphorylated bicycles. The structure of all these compounds was unequivocally determined by NMR spectroscopy and mass spectrometry, and, based on the results obtained, a mechanistic scheme for the phosphorylation reaction of these adducts to afford the corresponding phosphorylbicycles is proposed.
- Sousa, Carlos A. D.,Vale, M. Luisa C.,Rodriguez-Borges, Jose E.,Garcia-Mera, Xerardo
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- A Universally Applicable Methodology for the Gram-Scale Synthesis of Primary, Secondary, and Tertiary Phosphines
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Although organophosphine syntheses have been known for the better part of a century, the synthesis of phosphines still represents an arduous task for even veteran synthetic chemists. Phosphines as a class of compounds vary greatly in their air sensitivity, and the misconception that it is trivial or even easy for a novice chemist to attempt a seemingly straightforward synthesis can have disastrous results. To simplify the task, we have previously developed a methodology that uses benchtop intermediates to access a wide variety of phosphine oxides (an immediate precursor to phosphines). This synthetic approach saves the air-free handling until the last step (reduction to and isolation of the phosphine). Presented herein is a complete general procedure for the facile reduction of phosphonates, phosphinates, and phosphine oxides to primary, secondary, and tertiary phosphines using aluminum hydride reducing agents. The electrophilic reducing agents (iBu)2AlH and AlH3 were determined to be vastly superior to LiAlH4 for reduction selectivity and reactivity. Notably, it was determined that AlH3 is capable of reducing the exceptionally resistant tricyclohexylphosphine oxide, even though LiAlH4 and (iBu)2AlH were not. Using this new procedure, gram-scale reactions to synthesize a representative range of primary, secondary, and tertiary phosphines (including volatile phosphines) were achieved reproducibly with excellent yields and unmatched purity without the need for a purification step.
- Rinehart, N. Ian,Kendall, Alexander J.,Tyler, David R.
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- Investigation of non-Rehm-Weller kinetics in the electron transfer from trivalent phosphorus compounds to singlet excited sensitizers
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Singlet excited states (1S* and 1S +*) of neutral and monocationic sensitizers, S and S +, respectively, were quenched by electron transfer (ET) from a variety of trivalent phosphorus compounds (Z3P). The quenching rate constants kq, which are equal to the rate constants kET of the ET from Z3P to 1S* or 1S+*, were determined by the Stern-Volmer method. The logarithm of kET was plotted against free-energy change ΔG0 of the ET. The plot deviated upward from the line predicted by the Rehm-Weller (RW) theory in the endothermic region, the deviation being larger in the ET to a neutral acceptor 1S* than in the ET to a cationic acceptor 1S+*. Such a kinetic behavior is in sharp contrast to that observed in the ET from amines (R 3N), where the ET to either neutral or cationic acceptor takes place according to the RW prediction. The ET from a donor, Z3P or R 3N, to a neutral acceptor 1S* is a charge-separation type, during which electrostatic attraction between the donor and the acceptor is generated, whereas the ET to a cationic acceptor 1S+* is a charge-shift type, which results in neither electrostatic attraction nor repulsion. Difference in kinetics-energetics relationship by the type of ET, which is not recognized in the ET from R3N donor, becomes "visible" when Z 3P is used as a donor. Copyright 2013 John Wiley & Sons, Ltd. The rate constants kET of electron transfer from trivalent phosphorus compounds to singlet photoexcited sensitizers were determined by the Stern-Volmer method. LogkET-ΔG0 plots were found to deviate upward from the line predicted by the Rehm-Weller theory, with deviation being larger in ET to neutral acceptors than in ET to cationic acceptors. Copyright
- Yasui, Shinro,Tsujimoto, Munekazu
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- Electrochemical Enabled Cascade Phosphorylation of N?H/O?H/S?H Bonds with P?H Compounds: An Efficient Access to P(O)-X Bonds
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An electrochemical three component cascade phosphorylation reaction of various heteroatoms-containing nucleophiles including carbazoles, indoles, phenols, alcohols, and thiols with Ph2PH has been established. Electricity is used as the “traceless” oxidant and water and air are utilized as the “green” oxygen source. All kinds of structurally diverse organophosphorus compounds with P(O)-N/P(O)-O/P(O)-S bonds are assembled in moderate to excellent yields (three categories of phosphorylation products, 50 examples, up to 97 % yield). A tentative free radical course is put forward to rationalize the reaction procedure.
- Abdukader, Ablimit,Dong, Xiaojuan,Jin, Weiwei,Liu, Chenjiang,Wang, Bin,Wang, Ruige,Xia, Yu,Xue, Fei,Zhang, Yonghong
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supporting information
p. 14931 - 14935
(2021/10/06)
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- Application of heteropolyacid in catalytic synthesis of material compound
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The invention provides an application of heteropolyacid in catalytic synthesis of a diarylphosphonate compound. The method is characterized by comprising the following steps: in a protective gas atmosphere, taking diarylphosphonic acid and halogenated alkane as raw materials, heteropolyacid as a catalyst and an organic solvent as a solvent, and performing reacting to obtain the diarylphosphonate compound. According to the preparation method disclosed by the invention, only an extremely small amount of catalyst is needed, the reaction temperature is relatively mild, the reaction time can be obviously shortened, the yield and purity are relatively high, and an unexpected technical effect is achieved.
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Paragraph 0044-0049; 0062-0063
(2021/04/14)
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- Tf2O/DMSO-Promoted P-O and P-S Bond Formation: A Scalable Synthesis of Multifarious Organophosphinates and Thiophosphates
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A Tf2O/DMSO-based system for the dehydrogenative coupling of a wide range of alcohols, phenols, thiols, and thiophenols with diverse phosphorus reagents has been developed. This metal- and strong-oxidant-free strategy provides a facile approach to a great variety of organophosphinates and thiophosphates. The simple reaction system, good functional-group tolerance, and broad substrate scope enable the application of this method to the modification of natural products and the direct synthesis of bioactive molecules and flame retardants.
- Shen, Jian,Li, Qi-Wei,Zhang, Xin-Yue,Wang, Xue,Li, Gui-Zhi,Li, Wen-Zuo,Yang, Shang-Dong,Yang, Bin
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supporting information
p. 1541 - 1547
(2021/04/05)
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- Visible light induced hydrophosphinylation of unactivated alkenes catalyzed by salicylaldehyde
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An air and water insensitive visible light induced hydrophosphinylation of unactivated alkenes is reported. A small amount of a simple and cheap compound, salicylaldehyde, is used as a photosensitizer. The reaction is carried out in a basic aqueous solution which enables the deprotonated salicylaldehyde to show visible light absorption.
- Cao, Peng,Chen, Tian,Fan, Jiaye,Hu, Ping,Li, Miaomiao,Li, Qianggen,Li, Yang,Wang, Bi-Qin,Wang, Simin,Xiong, Fuying,Yuan, Zeqin
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supporting information
p. 3600 - 3606
(2021/06/06)
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- Nickel-Catalyzed Electrosynthesis of Aryl and Vinyl Phosphinates
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A mild and useful nickel-catalyzed electrochemical phosphonylation of aryl and vinyl bromides is described. We show that alkyl H-phenylphosphinates can be coupled electrochemically with functionalized aryl and vinyl bromides using very simple conditions (Fe/Ni anode, bench-stable nickel pre-catalyst, undivided cell, galvanostatic electrolysis) to furnish the corresponding aryl and vinyl phosphinates in satisfactory to good yields. Couplings can also be applied to heteroaromatic bromides with some limitations like increased propensity to hydro-dehalogenation.
- Daili, Farah,Ouarti, Abdelhakim,Pinaud, Marine,Kribii, Ibtihal,Sengmany, Stéphane,Le Gall, Erwan,Léonel, Eric
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p. 3452 - 3455
(2020/05/25)
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- A phosphoryl radical-initiated Atherton-Todd-type reaction under open air
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A phosphoryl radical-initiated Atherton-Todd-type reaction using air as the radical initiator and CHCl3 as the halogenating reagent for the phosphorylation of alcohols, phenols, and amines has been developed. This novel transformation provides a highly efficient route to important phosphinates, phosphinic amides, and phosphoramidates in up to 99% yield with a broad substrate scope under very mild conditions (48 examples).
- Ou, Yingcong,Huang, Yuanting,He, Zhenlin,Yu, Guodian,Huo, Yanping,Li, Xianwei,Gao, Yang,Chen, Qian
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supporting information
p. 1357 - 1360
(2020/02/11)
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- Novel method for preparing phosphonate through oxidative dehydrogenation coupled reaction of copper-catalyzed diarylphosphine oxide and alcohol
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The invention provides a method for efficiently and highly selectively synthesizing phosphonate derivatives containing different substituted functional groups. According to the method, cuprous iodideis used as a catalyst, 2,2'-dipyridyl is used as a ligand, pyridine is used as an alkali, oxygen is used as an oxidant, diarylphosphine oxide and an alcohol compound are used as reaction substrates, and an organic solvent is added into a reaction system. The method has the advantages that the catalyst and the oxidant are cheap and easily available; substrate applicability is high; reaction conditions are mild, safe and reliable; the selectivity of the obtained target products is close to 100%; and the yield of the target products is as high as 90% or above. The method overcomes the defects ofpoor reaction selectivity, complex reaction steps, low yield, need for reagents harmful to the environment and the like in the traditional synthesis of phosphonate derivatives, and has favorable industrial application prospects. The invention also provides the corresponding phosphonate derivatives containing different substituted functional groups.
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Paragraph 0014
(2020/12/14)
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- Preparation method of compound containing P-O bond or P-S bond
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The invention discloses a preparation method of a compound containing a P-O bond or a P-S bond. The method comprises the following steps: a compound containing hydroxyl or sulfydryl and a phosphorus reagent are taken as initial raw materials; then, the initial raw materials are put into an inert gas atmosphere; and under the action of trifluoromethanesulfonic anhydride (Tf2O) and dimethyl sulfoxide (DMSO), the compound containing hydroxyl or sulfydryl, the phosphorus reagent, the trifluoromethanesulfonic anhydride and the dimethyl sulfoxide in a molar ratio of (1-5): (1-2.5): (2-3): 2 react inan organic solvent at the reaction temperature of 25-100 DEG C for 6-20 hours to obtain the compound with the structural general formula (I). The reagents used in the method are low in toxicity and environmentally friendly, and use of precious metal catalysts high in price and toxicity is avoided. The reagents trifluoromethanesulfonic anhydride (Tf2O) and dimethyl sulfoxide (DMSO) used in the method are low in toxicity and very low in cost, so that the method is green, environment-friendly, high in economy and suitable for large-scale production.
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Paragraph 0172-0176
(2020/09/12)
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- Highly Efficient and Convenient Access to Phosphinates via CHCl3-Assisted Direct Phosphorylation between R2P(O)H and ROH by Phosphonium Salt Catalysis
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A mild, efficient, convenient and scalable method to synthesize phosphinates via direct phosphorylation between R2P(O)H and ROH was developed. All aromatic substrates completed this transformation with excellent yields (up to 98 %), and preliminary mechanistic studies suggest that a carbene-involving process from CHCl3 to CH2Cl2 facilitates the phosphorylation.
- Jiang, Zhiyu,Wang, Tianli,Yu, Xiaojun,Zhang, Hong-Su,Zhang, Song
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supporting information
(2020/05/25)
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- Electrochemical Dehydrogenative Coupling of Alcohols with Hydrogen Phosphoryl Compounds: A Green Protocol for P?O Bond Formation
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This study reports the environment-friendly electrochemical transformation of structurally diverse phosphorus compounds and alcohol into phosphonates in the presence of ammonium iodide as electrolyte and redox catalyst in acetonitrile at ambient temperature. This method for P?O bond formation exhibits remarkable features, such as transition metal- and oxidant-free conditions. A reliable mechanism is proposed after control and cyclic voltammetry experiments. (Figure presented.).
- Li, Qian-Yu,Swaroop, Toreshettahally R.,Hou, Cheng,Wang, Zi-Qiang,Pan, Ying-Ming,Tang, Hai-Tao
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p. 1761 - 1765
(2019/02/20)
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- A scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with RSH/ROH
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A practical, scalable electrochemical dehydrogenative cross-coupling of P(O)H compounds with thiols, phenols and alcohols in both an undivided cell and a continuous-flow setup is disclosed. Its broad substrate scope (>50 examples), good functional-group tolerance and scalability (>10 g) show potential for practical synthesis. A preliminary mechanistic study suggests that the phosphorus radicals are involved in the catalytic cycle.
- Li, Yujun,Yang, Qi,Yang, Liquan,Lei, Ning,Zheng, Ke
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supporting information
p. 4981 - 4984
(2019/05/21)
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- Electrochemical Dehydrogenative Phosphorylation of Alcohols for the Synthesis of Organophosphinates
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An eco-friendly and efficient method for the synthesis of organophosphinates via an electrochemical cross-dehydrogenative-coupling reaction between alcohols and secondary phosphine oxides has been developed. This electrochemical reaction was conducted at
- Deng, Lingling,Wang, Yang,Mei, Haibo,Pan, Yi,Han, Jianlin
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p. 949 - 956
(2019/01/14)
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- DCC-assisted direct esterification of phosphinic and phosphoric acids with O-nucleophiles
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A novel and efficient dicyclohexylcarbodiimide-promoted protocol for the selective and controllable esterification of P(O)OH compounds using O-nucleophiles (alcohols and phenols) as efficient esterification reagents is described. This method features a high efficiency and good functional-group tolerance, meaning a simple way to synthesize a broad spectrum of phosphinic and phosphoric acid esters from basic starting materials with moderate to excellent yields.
- Xiong, Biquan,Wang, Gang,Zhou, Congshan,Liu, Yu,Li, Jiandong,Zhang, Pangliang,Tang, Kewen
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supporting information
p. 239 - 244
(2017/11/20)
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- Method for preparing organophosphate compound from P(O)-OH-containing compound and alcohol through efficient esterification
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The invention provides a method for efficiently and highly selectively synthesizing an organophosphate derivative containing different substitute functional groups. The method is characterized by adopting a polypeptide catalyst as a condensation reagent, taking a P(O)-OH-containing compound and alcohol as reaction substrates, and adding an organic solvent in a reaction system. The method disclosed by the invention has the advantages that the catalyst is cheap in cost and easy to obtain; the substrate applicability is high; reaction conditions are mild, safe and reliable; the selectivity of an obtained target product is close to 100 percent, and the yield is up to 90 percent or more. According to the method provided by the invention, the defects of a traditional method for synthesizing an organophosphate compound that the reaction selectivity is poor, the reaction steps are tedious, the yield is low, reagents which are harmful to the environment are required to be used, and the like are solved, and a good industrial application prospect is obtained. Meanwhile, the invention also provides the corresponding organophosphate derivative containing different substitute functional groups.
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Paragraph 0017; 0018; 0019; 0020; 0021; 0022
(2017/07/21)
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- CDI-promoted direct esterification of P(O)-OH compounds with phenols
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A novel and efficient N,N′-carbonyl diimidazole-catalyzed protocol for the direct esterification of P(O)-OH compounds using phenols as efficient esterification reagents is illustrated. It is a simple way to synthesis a broad spectrum of functionalized O-aryl phosphinates, phosphonates, and phosphates from basic starting materials with moderate to excellent yields.
- Xiong, Biquan,Hu, Chenghong,Li, Haotian,Zhou, Congshan,Zhang, Pangliang,Liu, Yu,Tang, Kewen
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supporting information
p. 2482 - 2486
(2017/05/31)
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- Electrophilic Fluorination of Secondary Phosphine Oxides and Its Application to P-O Bond Construction
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A novel and efficient electrophilic fluorination of secondary phosphine oxides with Selectfluor has been achieved. This transformation provides direct access to phosphoric fluorides in up to 92% yield under mild conditions. In addition, P-O bond construction via a one-pot coupling process of secondary phosphine oxides with water or alcohols in the presence of Selectfluor leads to the formation of phosphinic acids or phosphinates in up to 96% yield.
- Chen, Qian,Zeng, Jiekun,Yan, Xinxing,Huang, Yulin,Wen, Chunxiao,Liu, Xingguo,Zhang, Kun
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p. 10043 - 10048
(2016/11/02)
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- Iron-catalyzed clean dehydrogenative coupling of alcohols with P(O)-H compounds: A new protocol for ROH phosphorylation
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An efficient oxygen-phosphoryl bond-forming reaction via iron-catalyzed cross dehydrogenative coupling has been developed. This transformation proceeds efficiently under oxidant- and halide-free reaction conditions with H2 liberation, and represents a straightforward method to prepare valuable organophosphoryl compounds from the readily available alcohols and P(O)-H compounds.
- Li, Chunya,Chen, Tieqiao,Han, Li-Biao
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supporting information
p. 14893 - 14897
(2016/10/11)
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- Efficient asymmetric synthesis of structurally diverse p-stereogenic phosphinamides for catalyst design
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The use of chiral phosphinamides is relatively unexplored because of the lack of a general method for the synthesis. Reported herein is the development of a general, efficient, and highly enantioselective method for the synthesis of structurally diverse P-stereogenic phosphinamides. The method relies on nucleophilic substitution of a chiral phosphinate derived from the versatile chiral phosphinyl transfer agent 1,3,2-benzoxazaphosphinine-2-oxide. These chiral phosphinamides were utilized for the first synthesis of readily tunable P-stereogenic Lewis base organocatalysts, which were used successfully for highly enantioselective catalysis.
- Han, Zhengxu S.,Zhang, Li,Xu, Yibo,Sieber, Joshua D.,Marsini, Maurice A.,Li, Zhibin,Reeves, Jonathan T.,Fandrick, Keith R.,Patel, Nitinchandra D.,Desrosiers, Jean-Nicolas,Qu, Bo,Chen, Anji,Rudzinski, Diandra M.,Samankumara, Lalith P.,Ma, Shengli,Grinberg, Nelu,Roschangar, Frank,Yee, Nathan K.,Wang, Guijun,Song, Jinhua J.,Senanayake, Chris H.
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supporting information
p. 5474 - 5477
(2015/04/27)
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- Direct aerobic oxidative esterification and arylation of P(O)-OH compounds with alcohols and diaryliodonium triflates
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Copper-catalyzed aerobic oxidative esterification of P(O)-OH compounds is achieved using alcohols as efficient esterification reagents, giving the expected products with good to moderate yields. Furthermore, it is shown that the arylation of P(O)-OH compounds proceeds efficiently to produce the corresponding products via the treatment of diaryliodonium triflates under mild reaction conditions. It is a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. The protocol is convenient for practical application. A plausible mechanism has been proposed for the reaction.
- Xiong, Biquan,Feng, Xiaofeng,Zhu, Longzhi,Chen, Tieqiao,Zhou, Yongbo,Au, Chak-Tong,Yin, Shuang-Feng
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p. 537 - 543
(2015/04/14)
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- T3P-assisted esterification and amidation of phosphinic acids
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A few phosphinic acids, such as phenylphosphinic acids, 1-hydroxy-3-phospholene 1-oxides and 1-hydroxyphospholane oxides are esterified with simple alcohols in the presence of propylphosphonic anhydride (T3P). If 1.1 equiv of the T3P reagent is used, the esterifications are fast and efficient at 25° C. In the case of more reactive models it was enough to apply 0.66 equiv of T3P at 85°C under microwave conditions. The amidation of 1-hydroxy-3-methyl-3-phospholene oxide could also be accomplished under similar conditions.
- Jablonkai, Erzsébet,Henyecz, Réka,Milen, Mátyás,Kóti, János,Keglevich, Gy?rgy
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p. 8280 - 8285
(2015/03/05)
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- Base-promoted O-deprotonation/alkylation reaction of P(O)-OH compounds with alkyl halides
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A novel base-promoted O-deprotonation/alkylation reaction of P(O)-OH compounds with alkyl halides has been developed. The protocol is practical, representing a simple way to produce a broad spectrum of functionalized phosphinates, phosphonates, and phosphates from basic starting materials with good to excellent yields. A plausible mechanism was proposed for this reaction.
- Xiong, Biquan,Ye, Qianqian,Feng, Xiaofeng,Zhu, Longzhi,Chen, Tieqiao,Zhou, Yongbo,Au, Chak-Tong,Yin, Shuang-Feng
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p. 9057 - 9063
(2015/03/05)
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- Arylphosphonylation and arylazidation of activated alkenes
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Two radical-mediated processes of activated alkenes, namely arylphosphonylation and arylazidation, are described. The difunctionalization of alkenes by a tandem process that involves radical addition, 1,4-aryl migration, and desulfonylation generates α-ar
- Kong, Wangqing,Merino, Estibaliz,Nevado, Cristina
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supporting information
p. 5078 - 5082
(2014/05/20)
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- Copper-promoted oxidative-fluorination of arylphosphine under mild conditions
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An efficient method for the synthesis of phosphoric fluoride via oxidative coupling between hydrophosphine oxide and NaF is reported. DDQ serves as the oxidizing reagent as well as the hydrogen acceptor. The process involves a Cu(ii) catalysis and exhibits great functional group tolerance under mild reaction conditions. the Partner Organisations 2014.
- Liu, Na,Mao, Liu-Liang,Yang, Bin,Yang, Shang-Dong
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supporting information
p. 10879 - 10882
(2014/10/15)
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- Synthesis of diverse aromatic oxophosphorus compounds by the Michaelis-Arbuzov-type reaction of arynes
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Arynes, generated in situ from o-(trimethylsilyl)aryl triflates by treatment with a fluoride, have been shown to react efficiently with various alkoxyphosphines via a mechanism similar to the Michaelis-Arbuzov reaction. Diverse aromatic oxophosphorus compounds, including derivatives with an ortho-ester function, have become easily available from a common aryne precursor by this method.
- Yoshida, Suguru,Hosoya, Takamitsu
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p. 583 - 585
(2013/07/05)
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- New quinoline-2, -3, and 4-yl-(amino) methylphosphonates: Synthesis and study on the C-P bond cleavage in quinoline-2 and -4 derivatives under acidic conditions
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Synthesis of new quinoline-(amino)methylphosphonic acids, their phosphonate esters, and phosphine oxides is presented. The desired new compounds were efficiently obtained by nucleophilic addition of phosphorous species to quinoline-derived Schiff bases. In addition, it was discovered that heating of quinolin-2 and quinolin-4-yl-(amino)-methylphosphonates with aqueous HCl leads to their decomposition resulting in a rupture of the C-P bond, rejecting of the phosphorus containing fragment, and formation of the corresponding secondary quinoline-2 and quinoline-4-alkylamines. Two alternative mechanistic pathways for this cleavage are postulated. Copyright
- Michalska, Joanna,Boduszek, Bogdan,Olszewski, Tomasz K.
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scheme or table
p. 617 - 624
(2011/12/04)
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- Catalytic hydrophosphorylation of dialkyl 2-allylmalonates
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The reaction of dialkyl hydrogen phosphites and diphenylphosphine oxide with dialkyl 2-allylmalonates in the presence of [Pd(Ph3P) 4] is studied. The addition of the hydrophosphoryl compounds to the multiple bond is established to proceed by the Markovnikov rule. The reaction is accompanied by the side process of malonate dealkoxycarbonylation whose contribution to the main process depends on the nature of the reagents.
- Reznikov,Skvortsov
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p. 1170 - 1176
(2008/02/12)
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- Aminophosphine oxides in a pyridine series. Studies on the cleavage of pyridine-2- and pyridine-4-yl-(N-benzylamino)-methyldiphenylphosphine oxides in acidic solutions
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The synthesis and reactions of 1-(N-benzylamino)-1-(2-pyridyl)- and 1-(N-benzylamino)-1-(4-pyridyl)-methyldiphenylphosphine oxides are described. It was found that these compounds were exceptionally easy to cleave in aqueous sulfuric acid solutions to form diphenylphosphinic acid and the corresponding N-(pyridylmethyl)-benzylamines. The structure of a single diastereoisomer, that is, the (R)-(+)-1-[N-(α-methylbenzylamino)]-1-(4-pyridyl)-(S)-methyldiphen ylphosphine oxide was determined by X-ray crystallography. The acidic alcoholysis of the selected model chiral pyridine aminophosphine oxides was investigated by means of 31P NMR spectroscopy. The cleavage kinetics were also studied. On the basis of the obtained results, a mechanism of the cleavage was formulated.
- Goldeman, Waldemar,Olszewski, Tomasz K.,Boduszek, Bogdan,Sawka-Dobrowolska, Wanda
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p. 4506 - 4518
(2007/10/03)
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- Mixed anhydrides: Key intermediates in carbamates forming processes of industrial interest
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Mixed anhydrides of carbonic acid with phosphonic or carbamic acid, are mimic of relevant biological systems, and behave as key intermediates in transesterification processes that afford carbamates of industrial interest. They are formed in the phosphonic acids mediated or direct transesterification reaction of organic carbonates with amines to afford carbamates and have been isolated and characterised in the solid state and solution. Their conversion into the products has been demonstrated to occur with high regioselectivity. The application of such intermediates in some synthetic processes is discussed.
- Aresta, Michele,Dibenedetto, Angela
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p. 685 - 690
(2007/10/03)
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- Irreversibility of single electron transfer occurring from trivalent phosphorus compounds to iron(III) complexes in the presence of ethanol
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Various types of trivalent phosphorus compounds (1; Ph(3-n)P(OR)n) underwent single electron transfer (SET) to unsubstituted (2H) and 5-chloro-substituted tris(1, 10-phenanthroline)iron(III) complexes (2Cl) in the presence of ethanol in acetonitrile, resulting in the reduction of 2 to the corresponding iron(II) complexes. The rate constants (kp) for the overall SET process were determined spectrophotometrically to show that within each series of 1 with an identical alkoxy group OR, log kp correlates linearly with the difference in the half-wave potentials (ΔE1/2) between 1 and 2. The slope of each correlation line gave an α-value for each series of 1. The α-values were significantly smaller than unity, indicating that the SET step is irreversible, even though this step is endothermic. The trivalent phosphorus radical cation 1.+ generated in the SET step undergoes a rapid ionic reaction with ethanol, which is certainly the origin of the irreversibility. Upon examining the α-values more closely, it was found that the transition state of the SET step becomes earlier with increasing bulkiness of the substituent OR. It is concluded that 1 and 2 form a tight encounter complex to undergo SET from the former to the latter.
- Yasui, Shinro,Itoh, Kenji,Tsujimoto, Munekazu,Ohno, Atsuyoshi
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p. 1311 - 1318
(2007/10/03)
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- Synthesis of a novel diarylphosphinic acid: A distorted ground state mimic and transition state analogue for amide hydrolysis
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We describe herein the synthesis of a new unsymmetrical diarylphosphinic acid, a hapten aimed to produce catalytic antibodies for the hydrolysis of heterocyclic amides. The phosphinate functionality was selected as a mimic both of the tetrahedral intermed
- Schuman, Marc,Lopez, Xabier,Karplus, Martin,Gouverneur, Véronique
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p. 10299 - 10307
(2007/10/03)
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- Formation of enantiomerically pure 1-Fluorovinyl and 1-fluoromethyl sulfoxides
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(Ss)-[Fluoro(p-tolylsulfinyl)methyl]diphenylphosphane oxide (2) was obtained with complete stereoselectivity from (fluoromethyl)diphenylphosphane oxide (3) and (S)-(-)-menthyl p-toluenesulfinate. 1-Fluorovinyl p-tolyl sulfoxides 1 were prepared in good yields by Horner-Wittig reaction of 2 with aldehydes, in excellent enantiomeric excess (ee). With ketones, yields were generally low. Stereoselectivity was high for aliphatic aldehydes, producing (Z) isomers, and for benzaldehydes, yielding the (E) isomers. A two-step, one-pot procedure for the conversion of 3 into 1 was also developed. Solvolysis of 2 provided the first route to enantiomerically pure (S)-1-(fluoromethyl)sulfinyl-4-methylbenzene (7).
- Van Steenis, Jan Hein,Boer, Philip W. S.,Van Der Hoeven, Harald A.,Van Der Gen, Arne
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p. 911 - 918
(2007/10/03)
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- Kinetic study on denomination of vic-dibromides with trivalent phosphorus compounds
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Various types of trivalent phosphorus compounds (I) brought about reductive debromination of vic-dibromides (2) to afford olefins. The reaction was accelerated by either electron-releasing substituents on the phosphorus of 1 or electron-with-drawing substituants on the α-carbon of 2. The substituent effects, along with the stereochemistry of the reaction, are consistent with an E1CB-like mechanism for the elimination of the two bromine atoms. That is, 1 initially undergoes nucleophilic attack upon a bromine of 2. At the transition state, a fractional positive charge is developed on the phosphorus of 1 and a fractional negative charge on the carbon of 2. This mechanism suggests the importance of an electronic character of the vic-dibromide in determining the relative ease of bromophilicity, carbophilicity, and basicity of the phosphorus of a trivalent phosphorus compound in a reaction with the dibromide. α 2001 John Wiley & Sons, Inc.
- Yasui, Shinro
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p. 217 - 222
(2007/10/03)
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- Quenching of a photosensitized dye through single-electron transfer from trivalent phosphorus compounds
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Various types of trivalent phosphorus compounds 1 undergo single-electron transfer (SET) to the photoexcited state of rhodamine 6G (Rho+(*)) in aqueous acetonitrile to quench the fluorescence from Rho+(*). The rate constants k(p) for the overall SET process were determined by the Stern-Volmer method. The rate is nearly constant at a diffusion-controlled limit in the region of E( 1/2 )(1) +), whereas log k(p) depends linearly on E( 1/2 )(1) in the region of E( 1/2 )(1) > 1.3 V, the slope of the correlation line being -αF/RT with α = 0.2. The potential at which the change in dependence of log k(p) on E( 1/2 )(1) occurs (1.3 V) is in accordance with the value of E( 1/2 )(Rho+(*)) (1.22 V) that has been obtained experimentally. Thus, the SET step is exothermic when E( 1/2 )(1) 1.3 V. The α-value (0.2) obtained in the endothermic region shows that the SET step from 1 to Rho+(*)is irreversible in this region. Trivalent phosphorus radical cation 1(·+) generated in the SET step undergoes an ionic reaction with water in the solvent rapidly enough to make the SET step irreversible. In contrast, the SET from amines 2 and alkoxybenzenes 3 to Rho+(*) is reversible when the SET step is endothermic, meaning that the radical cations 2(·+) and 3(·+) generated in the SET step undergo rapid 'back SET' in the ground state to regenerate 2 and 3.
- Yasui, Shinro,Tsujimoto, Munekazu,Itoh, Kenji,Ohno, Atsuyoshi
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p. 4715 - 4720
(2007/10/03)
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- Geometrical photoisomerization of (Z)-cyclooctene sensitized by aromatic phosphate, phosphonate, phosphinate, phosphine oxide and chiral phosphoryl esters
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Aromatic phosphate, phosphonate, phosphinate and phosphine oxide have been used as effective sensitizers for the geometrical photoisomerization of (Z)-cyclooctene (1Z) to its highly strained (E)-isomer (1E). Photosensitizations with phosphate and phosphonate gave moderate photostationary-state E/Z ratios of 0.14-0.17. A comparative study of the fluorescence quenching experiments and kinetic analysis of the product yield demonstrate that the photosensitized isomerization proceeds through a mixed mechanism that involves both singlet and triplet excited states. Triphenylphosphine oxide is not fluorescent and gave a low photostationary-state E/Z ratio of 0.05. Using (-)-menthyl or (-)-bornyl phosphate, phosphonate and phosphinate as chiral sensitizers, the enantiodifferentiating photoisomerization of 1Z was performed to afford optically active 1E in enantiomeric excesses ≤5%.
- Shi, Min,Inoue, Yoshihisa
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p. 2421 - 2427
(2007/10/03)
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- Preparation and ring-opening reactions of N-diphenylphosphinyl aziridines
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Monochiral N-Diphenyphosphinyl aziridines ('N-Dpp azinidines') may efficiently be prepared from monochiral 2-aminoalcohols. Such aziridines undergo ring-opening reaction with a variety of nucleophiles in good yield. Dephosphinylation is accomplished under mild conditions.
- Cantrill, Alex A.,Osborn, Helen M. I.,Sweeney, Joseph
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p. 2181 - 2208
(2007/10/03)
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- Investigation of the reaction between diphenylphosphine and carbon tetrachloride
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The mechanism of diphenyltrichloromethylphosphine (4) formation in the title reaction has been studied. It has been established that the diphenyltrichloromethylphosphine is formed in the multistep reaction sequence (Scheme 1), which involves the intermediacy of chlorodiphenylphosphine (2) and tetraphenyldiphosphine (3). This process is analogous to the formation of dialkyltrichloromethylphosphines in the dialkylphosphine / CCl4 reaction.
- Majewski, Piort
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p. 399 - 406
(2007/10/03)
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- Reaction of trivalent phosphorus compounds with an Fe(III) complex in the presence of alcohol. Single electron transfer accompanied by a P-O bond formation
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Reactions of various types of trivalent phosphorus compounds with iron(III) complex in the presence of ethanol have been examined kinetically, showing that the single electron transfer from the former compounds to the latter is followed by rapid reaction of the resulting trivalent phosphorus radical cations with ethanol.
- Yasui, Shinro,Itoh, Kenji,Tsujimoto, Munekazu,Ohno, Atsuyoshi
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p. 1019 - 1020
(2007/10/03)
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- Dichotomy in the reactivity of trivalent phosphorus compounds Z3P (Z = Ph, nBu, OR) observed in the photoreaction with a ruthenium complex
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Solutions of tris(2,2′-bipyridyl)ruthenium(II) dichloride (Ru2+) and various types of trivalent phosphorus compounds Z3P (Z = Ph, nBu, OR; 1) in methanol have been photolyzed with visible light at 20 °C under an argon atmosphere, resulting in the oxidation of I to the corresponding pentavalent oxo compounds Z3P=O and ligand exchange of Ru2+ with 1. The former process takes place via single-electron transfer (SET) from 1 to Ru2+ in the photoexcited state, Ru2+*, which gene-rates the radical cation intermediate Z3P*+ from 1. The latter results from nucleophilic attack of 1 upon Ru2+*. The results show that 1 can act either as an electron donor or as a nucleo-phile toward Ru2+*. The rate constants for both processes are estimated. An excellent linear correlation is found between the logarithm of the SET rate and the oxidation potential for both the aromatic and aliphatic trivalent phosphorus compounds examined here; the slope of the plot is much less negative than expected on the basis of Rehm-Weller theory. Such behavior in the SET rates is interpreted by comparison with SET quenching by amines. On the other hand, a dualparameter correlation analysis shows that the ligand exchange is regulated by both steric and electronic factors in 1. WILEY-VCH Verlag GmbH, 1997.
- Yasui, Shinro,Tsujimoto, Munekazu,Shioji, Kosei,Ohno, Atsuyoshi
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p. 1699 - 1707
(2007/10/03)
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- N-(diphenylphosphinothioyl)hydroxylamine: Preparation, characterisation and base-induced transposition of sulfur and oxygen atoms in its O-benzoyl derivative
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N-(Diphenylphosphinothioyl)hydroxylamine 5 has been prepared from Ph2P(S)Cl using H2NOSiMe3 and has been converted into its O-benzoyl derivative Ph2P(S)NHOCOPh 6. The principal reaction of the derivative 6 with base (NaOMe or ButNH2) is rearrangement, transposition of sulfur and oxygen giving Ph2P(O)NHSCOPh 7; this then reacts further, forming the phosphinic amide Ph2P(O)NH2 together with PhCO2Me or PhCONHBut. The rearrangement probably involves intramolecular nucleophilic displacement of benzoate by the P=S group of 6, forming an intermediate with P, N and S atoms in a three-membered ring.
- Harger, Martin J. P.
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p. 3205 - 3209
(2007/10/03)
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- Transposition of the phosphinoyl groups in the base-induced rearrangements of N,O-bis(diarylphosphinoyl)hydroxylamines
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Because the N- and O-phosphinoyl groups can change places prior to rearrangement, Ph2P(O)NHOP(O)Ar2 and Ar2P(O)NHOP(O)Ph2 (Ar = p-tolyl) both give mixtures of two phosphonamidic-phosphimic anhydrides, Ph(PhNH)P(O)OP(O)Ar2 and Ar(ArNH)P(O)OP(O)Ph2, on treatment with KOBu(t) in Bu(t)OH. The transposition of the phosphinoyl groups may involve phosphorane intermediates (7 and 9) having the P atom contained within a three-membered ring.
- Harger, Martin J. P.
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p. 4507 - 4508
(2007/10/03)
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- Reactions of 7-methoxyimino-4-methylchromene-2,8-dione with phosphines. Preparation of N-substituted 7-amino-8-hydroxy-4-methyl-2H-[1]-benzopyran-2-ones
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7-Methoxyimino-4-methylchromene-2,8-dione 2 reacts with triarylphosphines 1(a-d) to give the unexpected 7-arylomino-8-hydroxy-4-methyl-2H-[1]-benzopyran-2-ones 7(a-d) and methyl diarylphosphinates 8(a-d) in high yields. The reaction of 2 with trialkylphosphines 1(e,f) as well as with diphenylphosphine 15 leads to the formation of the N-dialkylphosphinoyl derivatives 11, 12, 14 and the N-diphenylphosphinoyl derivative 19, along with compounds 7(e,f). The methylation of compounds 7a, 7f, 11 and 19 is also studied and reaction mechanisms to explain the formation of the products obtained are suggested.
- Nicolaides, Demetrios N.,Awad, Raed Wajih,Litinas, Konstantinos E.,Malamidou-Xenikaki, Elizabeth
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p. 15007 - 15016
(2007/10/03)
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- Reacivity of Phosphorus-Centered Radicals Generated during the Photoreaction of Diphenylphosphinous Acid with 10-Methylacridinium Salt
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Diphenylphosphinous acid (1) reacts with 10-methylacridinium iodide (2a) in aqueous acetonitrile during irradiation by visible light under an argon atmosphere at 20 deg C to afford diphenylphosphinic acid (3) and 10-methylacridan (4).The effects of the solvent and atmosphere and the effect of added iodide ion (I(1-)) or iodine (I2) on the product distribution show that the mechanism involves initial single-electron transfer (SET) from 1 to 2a in the photoexcited state, by which cation radical 1(1+.) and dihydroacridinyl radical 2(.), are generated.Cation radical 1(1+.) undergoes electrophylic reaction with water in the solvent, and the resulting phosphoranyl radical decomposes through SET to iodine atom (I(.)) rather than unergoing β-scission, eventually giving 3.Protonation to 2(.) followed by reduction by I(1-) affords 4.These reaction sequences make up the catalytic I(.)/I(1-) couple.The results are interpreted on the basis of reported redox potentials.
- Yasui, Shinro,Shioji, Kosei,Ohno, Atsuyoshi,Yoshihara, Masakuni
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p. 2099 - 2105
(2007/10/02)
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- Reaction of a cation radical generated from trivalent phosphorus compound through single-electron transfer to arenediazonium salt
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A cation radical generated from a trivalent phosphorus compound through single-electron transfer to an arenediazonium salt undergoes both ionic and radical reactions. Relative ease of these reactions depends mainly on the number of phenyl ligands on the phosphorus atom.
- Yasui, Shinro,Shioji, Kosei,Ohno, Atsuyoshi
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p. 2695 - 2698
(2007/10/02)
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- Reaction of Three-coordinate Phosphorus Compounds with Organophosphorus Pseudohalogens. 3. Phosphonium and Phosphorane Intermediates in the Desulfurization and Dehalogenation of Bis(phosphinoyl) Disulfides. Influence of Lewis Acids on the Reaction Chemoselectivity
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The reactions of bis(phosphinoyl) disulfides RR1P(O)S-S-P(O)RR1 1 with PIII compounds have been investigated and various mechanistic features have been elucidated by variable-temperature 31P NMR spectroscopy.These studies show that in most cases phosphonium intermediates 5 and 6 are involved.In cases were ligands on PIII increase the stability of the five coordinate structures phosphorane intermediates are observed.In the isomerization 5 -> 6, the mode of decomposition (desulfurization, deoxygenation or dealkylation) to give stable end products is influenced by electronic and steric factors.The presence of the Lewis acid BF3 influences considerably the stability of the transient species 5 and 6 and the chemoselectivity of the reaction.
- Krawczyk, Ewa,Skowronska, Aleksandra,Michalski, Jan
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- THE EASY P-C-BOND CLEAVAGE OF FLUORINATED PHOSPHINE OXIDE
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Treatment of (1-acetamido-1-trifluoromethyl-2,2,2-trifluoroethyl)diphenyl phosphine oxide by OH-nucleophiles leads to the P-C(sp3) bond cleavage. Key words: (1-Acetamido-1-trifluoromethyl-2,2,2-trifluoroethyl)diphenyl phosphine oxide; hydrolysis; methanolysis; P-C bond cleavage.
- Aksinenko, A.Yu.,Pushin, A.N.,Sokolov, V.B.
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p. 249 - 252
(2007/10/02)
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- Solvation and metal ion effects on structure and reactivity of phosphoryl compounds. Part 2. Alkali metal ion catalysis in the demethylation of methyl di(3-nitrophenyl)phosphinate by iodide ion
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Second-order rate constants for the demethylation of methyl di(3-nitrophenyl)phosphinate by iodide in acetone-d6 at 25 deg C have been measured.For a series of iodide salts the rate increased in the order: NBu4I KI /= NaI LiI.The addition of crown ethers or D2O has a retarding effect on the reaction rate.The results are discussed in terms of the increase of the nucleofugality of the phosphinate group via the complexation of metal ions with the phosphoryl function.
- Modro, Agnes M.,Modro, Tomasz A.
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p. 469 - 472
(2007/10/02)
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