- Visible light-mediated, high-efficiency oxidation of benzyl to acetophenone catalyzed by fluorescein
-
An environmentally friendly aerobic oxidation of benzyl C(sp3)-H bonds to ketones via selective oxidation catalysis was developed. Fluorescein is an efficient photocatalyst with excellent chemical selectivity. The reaction has a wide substrate scope, and a successful gram-scale experiment demonstrated its potential industrial utility.
- Geng, Haoxing,Liu, Xin,Zhu, Qing
-
supporting information
(2021/12/20)
-
- Promoting charge separation in donor-acceptor conjugated microporous polymers: Via cyanation for the photocatalytic reductive dehalogenation of chlorides
-
Conjugated microporous polymers (CMPs) have emerged as promising heterogeneous photocatalysts for organic transformations owing to their structural designability and functional versatility. However, limited by the insufficient separation of the photo-generated excitons, their photocatalytic efficiency falls far short of expectations. Herein, we demonstrate a cyanation strategy to promote charge carrier separation in CMPs by selectively incorporating carbazole and cyano groups as electron-donating and electron-withdrawing units, respectively. The resulting CMPs feature π-extended donor (D)-acceptor (A) conjugation structures endowing them with distinct semiconducting properties, in which the efficient charge separation and transfer and wide visible-light absorption are facilitated. Compared to the cyano-free counterpart, the cyano-functionalized CMPs showed superior photocatalytic efficiency as exemplified by photocatalytic reductive dehalogenation of chlorides. More prominently, full recyclability of the designed CMPs as well as catalytic activity for at least ten runs without the loss of catalytic performance in photocatalytic reductive dehalogenation of chlorides demonstrated their robustness and sustainability. This journal is
- Deng, Jiyong,Fang, Zhengjun,Lan, Donghui,Liao, Yunfeng,Liu, Qingquan,Zhang, Weijie,Zhou, Xiang
-
p. 7151 - 7159
(2021/11/17)
-
- Photoinduced Acetylation of Anilines under Aqueous and Catalyst-Free Conditions
-
A green and efficient visible-light induced functionalization of anilines under mild conditions has been reported. Utilizing nontoxic, cost-effective, and water-soluble diacetyl as photosensitizer and acetylating reagent, and water as the solvent, a variety of anilines were converted into the corresponding aryl ketones, iodides, and bromides. With advantages of environmentally friendly conditions, simple operation, broad substrate scope, and functional group tolerance, this reaction represents a valuable method in organic synthesis.
- Yang, Yu-Ming,Yan, Wei,Hu, Han-Wei,Luo, Yimin,Tang, Zhen-Yu,Luo, Zhuangzhu
-
p. 12344 - 12353
(2021/09/02)
-
- A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for aerobic oxidation of alcohols
-
A sodium trifluoromethanesulfinate-mediated photocatalytic strategy for the aerobic oxidation of alcohols has been developed for the first time, and the photoredox aerobic oxidation of secondary and primary alcohols provided the corresponding ketones and carboxylic acids, respectively, in high to excellent yields.
- Zhu, Xianjin,Liu, Can,Liu, Yong,Yang, Haijun,Fu, Hua
-
p. 12443 - 12446
(2020/10/30)
-
- Redox-driven deracemization of secondary alcohols by sequential ether/O2-mediated oxidation and Ru-catalyzed asymmetric reduction
-
The deracemization of benzylic alcohols has been achieved using a redox-driven one-pot two-step process. The racemic alcohols were oxidized by bis(methoxypropyl) ether and oxygen to give the ketone intermediates, followed by an asymmetric transfer hydrogenation with a chiral ruthenium catalyst. This compatible oxidation/reduction process gave the enantiomerically enriched alcohols with up to 95% ee values.
- Yang, Bing,Cui, Peng,Chen, Yongsheng,Liu, Qixing,Zhou, Haifeng
-
supporting information
(2020/10/14)
-
- 2-Bromoanthraquinone as a highly efficient photocatalyst for the oxidation ofsec-aromatic alcohols: experimental and DFT study
-
Anthraquinones are recognized as high efficiency photocatalysts which can perform various redox reactions in aqueous or organic phases. We have experimentally proven that 2-BrAQ can undergo hydrogen transfer with an alpha-aromatic alcohol under light conditions, thereby efficiently oxidizing the aromatic alcohol to the corresponding product. The yield of 1-phenethanol to acetophenone can reach more than 96%. In subsequent catalyst screening experiments, it was found that the electronegativity of the substituent at the 2 position of the anthraquinone ring and the acidity of the solvent affect the photocatalytic activity of anthraquinones. After using various aromatic alcohol substrates, 2-BrAQ showed good conversion and selectivity for most aromatic alcohols, but showed C-C bond cleavage and low selectivity with non-α-position aromatic alcohols. In order to explore the mechanism of the redox reaction of 2-BrAQ in acetonitrile solution, the corresponding free radical reaction pathway was proposed and verified by density functional theory (DFT). Focusing on calculations for 2-BrAQ during the reaction and the first-step hydrogen transfer reaction between the 2-BrAQ triplet molecule and the 1-phenylethanol molecule, we recognized the changes that occurred during the reaction and thus have a deeper understanding of the redox reaction of anthraquinone compounds in organic systems.
- Chen, Guanghui,Liao, Shengfu,Liu, Jianguo,Liu, Qiying,Ma, Longlong,Yan, Long
-
p. 37014 - 37022
(2020/10/27)
-
- Thiourea-Mediated Halogenation of Alcohols
-
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
- Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
-
p. 12901 - 12911
(2020/11/26)
-
- Heterogeneous carbon nitride photocatalyst for C-C bond oxidative cleavage of vicinal diols in aerobic micellar medium
-
A green and efficient visible-light promoted aerobic oxidative C-C bond cleavage of vicinal diols in micellar medium has been developed. This protocol used graphitic carbon nitride with nitrogen vacancies (CN620) as a metal-free recyclable photocatalyst and CTAB as surfactant in water. Control experiments and the ESR results indicated that superoxide radicals and valence band holes played an important role in the reaction. Further isotope experiments suggested both a β-scission/HAT pathway and an oxidation/hydrolysis/dehydration pathway for the reaction, which is different from previous reports. The semiconductor/micellar catalyst system can be recycled at least 10 times without a significant reduction in activity. Furthermore, this reaction could be carried out under solar light irradiation and was applicable to large-scale reactions with similar results.
- Chen, Jiayang,Chen, Shengjun,Dong, Xinyu,Hong, Mei,Ni, Bangqing,Niu, Tengfei,Zhang, Tianhao
-
supporting information
p. 5042 - 5049
(2020/08/25)
-
- Isopropanol as a hydrogen source for single atom cobalt-catalyzed Wacker-type oxidation
-
The first example of a heterogeneous cobalt catalytic system for Wacker-type oxidation catalyzed by a single atom dispersed Co-N/C catalyst using alcohol as the hydrogen source under an oxygen atmosphere is presented. By combining a well-designed, controlled experiment and various methods of characterization, we determined that single atom cobalt was the active center rather than nanoparticle or oxide counterparts.
- An, Yue,Chen, Bo,Gao, Shuang,Huang, Guanwang,Luo, Huihui,Shang, Sensen,Wang, Lianyue
-
p. 2769 - 2773
(2020/06/17)
-
- Method for synthesizing chiral alcohol through deracemization
-
The invention relates to a method for synthesizing chiral alcohol (formula I) through deracemization. The preparation method provided by the invention is one-pot asymmetric cascade reaction, and comprises the following steps: 1), with racemic alcohol (formula II) as a raw material and dipropylene glycol dimethyl ether as a solvent, reacting at 120 DEG C for 12 hours, and performing a dehydrogenation reaction to produce intermediate ketone (formula III); and 2), directly adding 2.5mol% of a chiral diamine metal ruthenium complex as a catalyst into a reaction system, with 5 equivalents of sodiumformate as a hydrogen source and a mixed solution of methanol and water as a solvent, reacting at 50 DEG C for 12 hours under the protection of nitrogen, and performing asymmetric transfer hydrogenation to obtain the chiral alcohol (formula I). The method has the advantages of environment-friendly synthesis such as a simple and mild reaction condition, step economy and atomic economy; and in addition, a substrate has a wide application range, the enantioselectivity is high, and the method has a broad application prospect in synthesis of chiral alcohol pharmaceutical intermediates and fine chemical raw materials.
- -
-
Paragraph 0053-0055
(2019/07/29)
-
- Nickel-Catalyzed Addition of Arylboronic Acids to Alkyl Nitriles for Synthesis of Aryl Ketones in Fluorinated Solvent
-
A mild and efficient nickel-catalyzed addition of arylboronic acids to alkyl nitriles in a fluorinated solvent for the synthesis of various aryl ketones is described. A broad range of arylboronic acids and alkyl nitriles were investigated, and the desired products were obtained with good to excellent yields under the optimized conditions. This method provides an opportunity for the synthesis of aryl ketones from alkyl nitriles, especially acetonitrile, with a non-noble metal catalyst in one pot.
- Tu, Dong-Huai,Li, Yang,Zhao, Bo,Gu, Yu-Jie,Wang, Bo,Lu, Ju-You,Lu, Jian
-
supporting information
p. 593 - 596
(2017/12/06)
-
- Regio- and chemoselective rearrangement of terminal epoxides into methyl alkyl and aryl ketones
-
The development of the highly active pincer-type rhodium catalyst 2 for the nucleophilic Meinwald rearrangement of functionalised terminal epoxides into methyl ketones under mild conditions is presented. An excellent regio- and chemoselectivity is obtained for the first time for aryl oxiranes.
- Tian, Yingying,Jürgens, Eva,Kunz, Doris
-
supporting information
p. 11340 - 11343
(2018/10/31)
-
- Pd(II)-Catalyzed Denitrogenative and Desulfinative Addition of Arylsulfonyl Hydrazides with Nitriles
-
A Pd(II)-catalyzed denitrogenative and desulfinative addition of arylsulfonyl hydrazides with nitriles has been successfully achieved under mild conditions. This transformation is a new method for the addition reaction to nitriles with arylsulfonyl hydrazides as arylating agent, thus providing an alternative synthesis of aryl ketones. The reported addition reaction is tolerant to many common functional groups, and works well in the presence of electron-donating and electron-withdrawing substituents. Notably, the reported denitrogenative and desulfinative addition was also appropriate for alkyl nitriles, making this newly developed transformation attractive.
- Meng, Mengting,Yang, Liangfeng,Cheng, Kai,Qi, Chenze
-
p. 3275 - 3284
(2018/03/25)
-
- Transformation of Alkynes into Chiral Alcohols via TfOH-Catalyzed Hydration and Ru-Catalyzed Tandem Asymmetric Hydrogenation
-
A novel full atom-economic process for the transformation of alkynes into chiral alcohols by TfOH-catalyzed hydration coupled with Ru-catalyzed tandem asymmetric hydrogenation in TFE under simple conditions has been developed. A range of chiral alcohols was obtained with broad functional group tolerance, good yields, and excellent stereoselectivities.
- Liu, Sensheng,Liu, Huan,Zhou, Haifeng,Liu, Qixing,Lv, Jinliang
-
supporting information
p. 1110 - 1113
(2018/02/23)
-
- Easy Access to Enantiopure (S)- and (R)-Aryl Alkyl Alcohols by a Combination of Gold(III)-Catalyzed Alkyne Hydration and Enzymatic Reduction
-
Chemoenzymatic one-pot processes based on the combination of metal catalysis and biocatalysis open up highly attractive perspectives regarding the production of enantiopure compounds. By combining a gold-catalyzed hydration reaction with an enzymatic reduction, we present a straightforward and atom-economical chemoenzymatic method for the synthesis of secondary alcohols with excellent optical purity. Efficient cofactor recycling exploits the solvent of the metal-catalyzed step as an auxiliary substrate for the enzymatic step.
- Schaaf, Patricia,Gojic, Vladimir,Bayer, Thomas,Rudroff, Florian,Schnürch, Michael,Mihovilovic, Marko D.
-
p. 920 - 924
(2018/02/23)
-
- One-pot synthesis of chiral alcohols from alkynes by CF3SO3H/ruthenium tandem catalysis
-
A practical one-pot synthesis of chiral alcohols from readily available alkynes via tandem catalysis by the combination of CF3SO3H and a fluorinated chiral diamine Ru(ii) complex in aqueous CF3CH2OH is described. Very interestingly, the combination of fluorinated catalysts and solvent exhibits a positive fluorine effect on the reactivity and enantioselectivity. A range of chiral alcohols with wide functional group tolerance was obtained in high yield and excellent stereoselectivity under simple and mild conditions.
- Liu, Huan,Liu, Sensheng,Zhou, Haifeng,Liu, Qixing,Wang, Chunqin
-
p. 14829 - 14832
(2018/04/30)
-
- Preparation method of aromatic ketone
-
The invention discloses a preparation method of aromatic ketone. Under the effects of a palladium catalyst and a nitrogen-containing ligand, nitrile compounds and arylsulfonylhydrazide take desulfurization addition reaction in an organic solvent; after the reaction is completed, post treatment is performed to obtain aromatic ketone. The reaction is applicable to aromatic nitrile compounds, and isalso applicable to aliphatic nitrile compounds; the reaction realizes the wide substrate applicability and functional group tolerance; the potential application value is realized in the aspect of aryl-carbonyl building.
- -
-
Paragraph 0056; 0057; 0058; 0060
(2018/09/11)
-
- Secondary Phosphine Oxides as Multitalented Preligands En Route to the Chemoselective Palladium-Catalyzed Oxidation of Alcohols
-
Secondary phosphine oxides O=PHR2 (SPOs) were identified as multitalented preligands for the chemoselective Pd-catalyzed oxidation of alcohols by a hydrogen-abstracting methodology. SPOs were found to promote the hydrogen-abstraction step as well as hydrogen transfer to a Michael acceptor by generating a putative active H?Pd species. The catalytic system operates under neutral conditions and was proven to be compatible with various electrophilic and nucleophilic functionalities within the substrates as well as water- and air-sensitive functional groups.
- Vasseur, Alexandre,Membrat, Romain,Gatineau, David,Tenaglia, Alphonse,Nuel, Didier,Giordano, Laurent
-
p. 728 - 732
(2017/03/13)
-
- Stereoselective amination of racemic sec-alcohols through sequential application of laccases and transaminases
-
A one-pot/two-step bienzymatic asymmetric amination of secondary alcohols is disclosed. The approach is based on a sequential strategy involving the use of a laccase/TEMPO catalytic system for the oxidation of alcohols into ketone intermediates, and their following transformation into optically enriched amines by using transaminases. Individual optimizations of the oxidation and biotransamination reactions have been carried out, studying later their applicability in a concurrent process. Therefore, 17 racemic (hetero) aromatic sec-alcohols with different substitutions in the aromatic ring have been converted into enantioenriched amines with good to excellent selectivities (90-99% ee) and conversion values (67-99%). The scalability of the process was also demonstrated when two different amine donors were used in the transamination step, such as isopropylamine and cis-2-buten-1,4-diamine. Satisfyingly, both sacrificial amine donors can shift the equilibrium toward the amine formation, leading to the corresponding isolated enantioenriched amines with good to excellent results.
- Martínez-Montero, Lía,Gotor, Vicente,Gotor-Fernández, Vicente,Lavandera, Iván
-
supporting information
p. 474 - 480
(2017/06/23)
-
- In vitro biocatalytic pathway design: Orthogonal network for the quantitative and stereospecific amination of alcohols
-
The direct and efficient conversion of alcohols into amines is a pivotal transformation in chemistry. Here, we present an artificial, oxidation-reduction, biocatalytic network that employs five enzymes (alcohol dehydrogenase, NADP-oxidase, catalase, amine dehydrogenase and formate dehydrogenase) in two concurrent and orthogonal cycles. The NADP-dependent oxidative cycle converts a diverse range of aromatic and aliphatic alcohol substrates to the carbonyl compound intermediates, whereas the NAD-dependent reductive aminating cycle generates the related amine products with >99% enantiomeric excess (R) and up to >99% conversion. The elevated conversions stem from the favorable thermodynamic equilibrium (K′eq = 1.88 × 1042 and 1.48 × 1041 for the amination of primary and secondary alcohols, respectively). This biocatalytic network possesses elevated atom efficiency, since the reaction buffer (ammonium formate) is both the aminating agent and the source of reducing equivalents. Additionally, only dioxygen is needed, whereas water and carbonate are the by-products. For the oxidative step, we have employed three variants of the NADP-dependent alcohol dehydrogenase from Thermoanaerobacter ethanolicus and we have elucidated the origin of the stereoselective properties of these variants with the aid of in silico computational models.
- Knaus, Tanja,Cariati, Luca,Masman, Marcelo F,Mutti, Francesco G.
-
p. 8313 - 8325
(2017/10/19)
-
- Stereoelectronic effects in the reaction of aromatic substrates catalysed by: Halomonas elongata transaminase and its mutants
-
A transaminase from Halomonas elongata and four mutants generated by an in silico-based design were recombinantly produced in E. coli, purified and applied to the amination of mono-substituted aromatic carbonyl-derivatives. While benzaldehyde derivatives were excellent substrates, only NO2-acetophenones were transformed into the (S)-amine with a high enantioselectivity. The different behaviour of wild-type and mutated transaminases was assessed by in silico substrate binding mode studies.
- Contente, Martina Letizia,Planchestainer, Matteo,Molinari, Francesco,Paradisi, Francesca
-
p. 9306 - 9311
(2016/10/13)
-
- Ketone synthesis method through alkyne hydrolysis
-
The invention discloses a ketone synthesis method through alkyne hydrolysis. The method comprises the following steps: adding alkyne, a catalyst [(IPr)AuCl], a solvent methanol, and water into a reactor, carrying out reactions for several hours at a temperature of 110 to 120 DEG C, cooling to the room temperature, carrying out rotary evaporation to remove the solvent, and performing column separation to obtain target compounds. Compared with conventional ionic gold catalyst, the provided method directly uses gold chloride [(IPr)AuCl] as the catalyst, alkyne is hydrolyzed into ketone, the yield is high, the selectivity is complete, and thus the method has an important meaning for organic synthesis and environment protection.
- -
-
Paragraph 0053-0056
(2017/05/02)
-
- Synthesis of a-Alkylated Ketones via Tandem Acceptorless Dehydrogenation/a-Alkylation from Secondary and Primary Alcohols Catalyzed by Metal-Ligand Bifunctional Iridium Complex [CpIr(2,2′-bpyO)(H2O)]
-
A new strategy for the synthesis of α-alkylated ketones via tandem acceptorless dehydrogenation/α-alkylation from secondary and primary alcohols was proposed and accomplished. In the presence of metal-ligand bifunctional iridium complex [CpIr(2,2′-bpyO)(H2O)], various desirable products were obtained in high yields. Compared with previous methods for the direct dehydrogenative coupling of secondary alcohols with primary alcohols to α-alkylated ketones, this protocol has obvious advantages including complete selectivity for α-alkylated ketones and more environmentally benign conditions. Notably, the study also exhibited the potential to develop tandem reactions catalyzed using a metal-ligand bifunctional iridium complex.
- Wang, Rongzhou,Ma, Juan,Li, Feng
-
p. 10769 - 10776
(2015/11/18)
-
- Palladium catalyzed decarboxylative acylation of arylboronic acid with ethyl cyanoacetate as a new acylating agent: Synthesis of alkyl aryl ketones
-
Palladium catalyzed acylation of arylboronic acid containing various functional groups was performed efficiently by ethyl cyanoacetate/substituted ethyl cyanoacetate as the acylating agent in aqueous triflic acid medium. The alkyl aryl ketones were obtained in good to excellent yields, first by addition of arylboronic acid to the nitrile group of ethyl cyanoacetate and their derivatives, followed by in situ decarboxylation of the resulting β-ketoester.
- Yousuf, Md,Das, Tuluma,Adhikari, Susanta
-
p. 8763 - 8770
(2015/11/10)
-
- Regioselective hydration of terminal alkynes catalyzed by a neutral gold(I) complex [(IPr)AuCl] and one-pot synthesis of optically active secondary alcohols from terminal alkynes by the combination of [(IPr)AuCl] and Cp?RhCl[(R, R)-TsDPEN]
-
A neutral gold(I) complex [(IPr)AuCl] (IPr = 1,3-bis(diisopropylphenyl)imidazol-2-ylidene) was found to be a highly effective catalyst for the hydration of terminal alkynes, including aromatic alkynes and aliphatic alkynes. The desired methyl ketones were obtained in high yields with complete regioselectivities. Furthermore, a series of optically active secondary alcohols could be obtained in high yield with good to excellent enatioselectivities via one-pot sequential hydration/asymmetric transfer hydrogenation (ATH) from terminal alkynes by the combination of of [(IPr)AuCl] and Cp?RhCl[(R,R)-TsDPEN] (Cp? = pentamethylcyclopentadienyl, TsDPEN = N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine). Notably, this research exhibited the potential of the direct use of neutral gold(I) complexes instead of cationic ones as catalysts for the activation of multiple bonds for organic synthesis.
- Li, Feng,Wang, Nana,Lu, Lei,Zhu, Guangjun
-
p. 3538 - 3546
(2015/04/14)
-
- Ruthenium(II)-NNN complex catalyzed Oppenauer-type oxidation of secondary alcohols
-
Highly efficient Oppenauer-type oxidation of secondary alcohols to the corresponding ketones has been realized by means of the ruthenium(II) complex catalysts bearing a 2-(benzoimidazol-2-yl)-6-(3,5-dimethylpyrazol-1-yl)pyridine ligand. The oxidation reaction underwent in the presence of acetone as oxidant under mild conditions, reaching final TOF values up to 3960 h-1. The hemilability of the ligand is attributed to the high catalytic activity of these Ru(II) complexes.
- Wang, Qingfu,Du, Wangming,Liu, Tingting,Chai, Huining,Yu, Zhengkun
-
p. 1585 - 1588
(2014/03/21)
-
- Silver-mediated fluorination of potassium aryltrifluoroborates with Selectfluor Dedicated to Professor Andrea Vasella on the occasion of his 71st birthday
-
A simple and practical procedure for the silver-mediated fluorination of aryl- and heteroaryltrifluoroborates with electrophilic fluorine from Selectfluor and LiOH·H2O is presented. The reaction procedure is simple and easy to set up, the process produces fluorinated arenes and heteroarenes in good to excellent yields and a wide range of electronically and structurally diverse substrates are tolerated.
- Dubbaka, Srinivas Reddy,Narreddula, Venkateswara Reddy,Gadde, Satyanarayana,Mathew, Thresen
-
p. 9676 - 9681
(2015/01/08)
-
- FLUORINATION OF ARYL COMPOUNDS
-
The invention provides compositions and methods of using the compositions in fluorinating aryl precursors containing a leaving group replaceable by a fluorine atom. The compositions include a metal ion source, a electrophilic fluorine source, a base, and a compound, which is an aryl precursor of the aryl fluoride, and which has a leaving group replaceable by the fluorine atom. Exemplary methods of the invention make use of such compositions and methods to prepare an aryl fluoride compound. In an exemplary embodiment, the electrophilic fluorine source is a source of 18F.
- -
-
Paragraph 00117; 00118-00121
(2014/07/22)
-
- Fluorination of aryl boronic acids using acetyl hypofluorite made directly from diluted fluorine
-
Aryl boronic acids or pinacol esters containing EDG were converted in good yields and fast reactions to the corresponding aryl fluorides using the readily obtainable solutions of AcOF. In reactions with aryl boronic acids containing EWG at the para position, there are two competing forces: one directing the fluorination to take place ortho to the boronic acid and the other, toward an ipso substitution. With EWG meta to the boronic acid, substitution ipso to the boron moiety takes place in good yields.
- Vints, Inna,Gatenyo, Julia,Rozen, Shlomo
-
p. 11794 - 11797
(2014/01/06)
-
- Copper-mediated fluorination of arylboronate esters. Identification of a Copper(III) fluoride complex
-
A method for the direct conversion of arylboronate esters to aryl fluorides under mild conditions with readily available reagents is reported. Tandem reactions have also been developed for the fluorination of arenes and aryl bromides through arylboronate ester intermediates. Mechanistic studies suggest that this fluorination reaction occurs through facile oxidation of Cu(I) to Cu(III), followed by rate-limiting transmetalation of a bound arylboronate to Cu(III). Fast C-F reductive elimination is proposed to occur from an aryl-copper(III)-fluoride complex. Cu(III) intermediates have been generated independently and identified by NMR spectroscopy and ESI-MS.
- Fier, Patrick S.,Luo, Jingwei,Hartwig, John F.
-
supporting information
p. 2552 - 2559
(2013/03/29)
-
- Enantioselective oxidation of racemic secondary alcohols catalyzed by chiral Mn(iii)-salen complexes with N-bromosuccinimide as a powerful oxidant
-
We demonstrate an efficient enantioselective oxidation of secondary alcohols catalyzed by Mn(iii)-salen complex using N-bromosuccinimide (NBS) as the oxidant. The new protocol is very efficient for the oxidative kinetic resolution of a variety of secondary alcohols, including ortho-substituted benzylic alcohols. The Royal Society of Chemistry 2012.
- Xu, Daqian,Wang, Shoufeng,Shen, Zhiqiang,Xia, Chungu,Sun, Wei
-
supporting information
p. 2730 - 2732
(2012/11/07)
-
- Exploiting the enzymatic machinery of Arthrobacter atrocyaneus for oxidative kinetic resolution of secondary alcohols
-
We evaluated Arthrobacter atrocyaneus (R1AF57) as producer of oxidoreductases for oxidative kinetic resolution of racemic secondary alcohols via oxidation reaction. This bacterium was isolated from Amazon soil samples using medium enriched with (RS)-1-(4-methylphenyl)ethanol as a carbon source. The kinetic resolution of several secondary alcohols through enantioselective oxidation mediated by resting cells and growing cells of A. atrocyaneus was efficiently achieved for the most alcohols. In general, it was possible to obtain only the (S)-enantiomer from (RS)-1-arylethanols.
- Silva, Camila R.,Souza, Juliana C.,Araujo, Lidiane S.,Kagohara, Edna,Garcia, Thais P.,Pelizzari, Vivian H.,Andrade, Leandro H.
-
-
- Solvent-free hydration of alkynes over a heterogeneous silver exchanged silicotungstic acid catalyst
-
Silver exchanged silicotungstic acid (AgSTA) catalysts were prepared and characterized by X-ray diffraction, FT-IR spectroscopy, laser Raman, temperature programmed desorption of ammonia, FT-IR pyridine adsorption and X-ray photo electron spectroscopy. The activity of the catalysts was evaluated for the hydration of non-activated alkynes to corresponding carbonyl compounds without addition of any acid co-catalyst under solvent-free conditions. The highest catalytic activity was obtained for the catalyst with partially silver exchanged STA. This catalytic system provides one of the most straight forward syntheses of carbonyl compounds from terminal alkynes with Markovnikov-type regioselectivity. The catalyst can be recovered by simple filtration and is reusable without loss of activity and selectivity. A plausible reaction mechanism for the AgSTA catalyzed hydration of alkynes is proposed.
- Venkateswara Rao,Sai Prasad,Lingaiah
-
experimental part
p. 1507 - 1514
(2012/06/01)
-
- Electrophilicities of symmetrically substituted 1,3-diarylallyl cations
-
Kinetics of the reactions of nine symmetrically substituted 1,3-diarylallyl cations with different nucleophiles were studied photometrically in dichloromethane, acetonitrile, and DMSO solutions. The second-order rate constants k2 were found to follow the correlation log k2 = sN(N + E). The electrophilicity parameters E of the title cations were derived, using the known values of sN and N of the nucleophilic reaction partners, and compared with the electrophilicities of analogously substituted benzhydrylium ions. Good linear correlations were found between the electrophilicities E and the quantum chemically calculated gas-phase methyl anion affinities of the allyl cations and the σ+ constants of the substituents X.
- Troshin, Konstantin,Schindele, Claus,Mayr, Herbert
-
experimental part
p. 9391 - 9408
(2012/01/06)
-
- CYCLIC INHIBITORS OF 11BETA-HYDROXYSTEROID DEHYDROGENASE 1
-
This invention relates to novel compounds of the Formula Ik, Im1, Im2, Im5, In1, In2, In5, Io1, Io2, Io5, Ip1, Ip3, pharmaceutically acceptable salts thereof, and pharmaceutical compositions thereof, which are useful for the therapeutic treatment of diseases associated with the modulation or inhibition of 11β-HSD1 in mammals. The invention further relates to pharmaceutical compositions of the novel compounds and methods for their use in the reduction or control of the production of cortisol in a cell or the inhibition of the conversion of cortisone to cortisol in a cell.
- -
-
Page/Page column 53
(2011/01/05)
-
- Hydrogen-bonding-promoted oxidative addition and regioselective arylation of olefins with aryl chlorides
-
The first, general, and highly efficient catalytic system that allows a wide range of activated and unactivated aryl chlorides to couple regioselectively with olefins has been developed. The Heck arylation reaction is likely to be controlled by the oxidative addition of ArCl to Pd(0). Hence, an electron-rich diphosphine, 4-MeO-dppp, was introduced to facilitate the catalysis. Solvent choice is critical, however; only sluggish arylation is observed in DMF or DMSO, whereas the reaction proceeds well in ethylene glycol at 0.1-1 mol % catalyst loadings, displaying excellent regioselectivity. Mechanistic evidence supports that the arylation is turnover-limited by the oxidative addition step and, most importantly, that the oxidative addition is accelerated by ethylene glycol, most likely via hydrogen bonding to the chloride at the transition state as shown by DFT calculations. Ethylene glycol thus plays a double role in the arylation, facilitating oxidative addition and promoting the subsequent dissociation of chloride from Pd(II) to give a cationic Pd(II)-olefin species, which is key to the regioselectivity observed.
- Ruan, Jiwu,Iggo, Jonathan A.,Berry, Neil G.,Xiao, Jianliang
-
supporting information; experimental part
p. 16689 - 16699
(2011/02/23)
-
- Hydrogen-bond-directed catalysis: Faster, regioselective and cleaner heck arylation of electron-rich olefins in alcohols
-
A general method for the regioselective Heck reaction of electronrich olefins is presented. Fast, highly regioselective Pd-catalysed α-arylation of electron-rich olefins, vinyl ethers (1a-d), hydroxyl vinyl ethers (1e,f), enamides (1g,h) and a substituted vinyl ether (1i) has been accomplished with a diverse range of aryl bromides (2a-r), for the first time, in cheap, green and easily available alcohols with no need for any halide scavengers or salt additives. The reaction proceeds with high efficiency, leading exclusively to the a-products, in 2-propanol and particularly in ethylene glycol. In the latter, the arylation can be catalysed at a palladium loading of 0.1 mol% and finish in as short a time as 0.5 h. The remarkable performance of the alcohol solvents in promoting a regiocontrol is attributed to their hydrogen-bond- donating capability, which is believed to facilitate the dissociation of halide anions from PdII, and hence, the generation of a key ionic Pd II-olefin intermediate responsible for the a product. This belief is further strengthened by the study of a benchmark arylation reaction in 21 different solvents. The study revealed that exclusive α-regioselective arylation takes place in almost all of the protic solvents, and there is a rough correlation between the α-arylation rates and the solvent parameter ETN. The method is simpler, cleaner and more general than those established thus far.
- Hyder, Zeynab,Ruan, Jiwu,Xiao, Jianliang
-
experimental part
p. 5555 - 5566
(2009/06/17)
-
- Axially chiral NHC-Pd(II) complexes in the oxidative kinetic resolution of secondary alcohols using molecular oxygen as a terminal oxidant
-
(Chemical Equation Presented) Axially chiral N-heterocyclic carbene (NHC) Pd(II) complexes were prepared from optically active 1,1′-binaphthalenyl- 2,2′-diamine (BINAM) and H8-BINAM and applied in the oxidative kinetic resolution of secondary alcohols using molecular oxygen as a terminal oxidant. The corresponding sec-alcohols can be obtained in good yields with moderate to good enantioselectivities.
- Chen, Tao,Jiang, Jia-Jun,Xu, Qin,Shi, Min
-
p. 865 - 868
(2007/10/03)
-
- Method For Preparation Of A Fluoroaromatic Compound From An Aminoaromatic Compound
-
The invention relates to a method for preparation of fluorinated aromatic compounds from the corresponding amines by replacement of the amino group with a fluorine atom. The method of preparation of a fluoroaromatic compound from an aromatic compound with at least one amino group on the aromatic ring is characterized by the reaction of said aromatic amine compound with a nitrosating agent in the presence of a source of boron trifluoride in an organic medium, and carrying out a thermal treatment of the reaction medium comprising the diazonium salt thus obtained to give the fluoroaromatic compound directly by decomposition of the diazonium salt without intermediate isolation thereof.
- -
-
Page/Page column 8
(2008/06/13)
-
- One-pot fluoro-de-diazoniation of anilines in organic medium
-
Treatment of anilines with tert-butyl nitrite in the presence of boron trifluoride in ortho-dichlorobenzene leads to in situ fluoro-de-diazoniation and affords the corresponding fluoroaromatics with fair yields. This process, conducted in organic medium without Broensted acids, does not require isolation of hazardous diazonium salts and reduces the amounts of wastes. The results of the first screening are given.
- Garel, Laurent,Saint-Jalmes, Laurent
-
p. 5705 - 5708
(2007/10/03)
-
- Ionic liquid-promoted, highly regioselective Heck arylation of electron-rich olefins by aryl halides
-
Palladium-catalyzed regioselective Heck arylation of the electron-rich olefins, vinyl ethers 1a-d, enamides 1e-g, and allyltrimethylsilane 1h, has been accomplished in imidazolium ionic liquids with a wide range of aryl bromides and iodides instead of the commonly used, but commercially unavailable and expensive, aryl triflates. The reaction proceeded with high efficiency and remarkable regioselectivity without the need for costly or toxic halide scavengers, leading exclusively to substitution by aryl groups of diverse electronic and steric properties at the olefinic carbon α to the heteroatom of 1a-g and β to the heteroatom of 1h. In contrast, the arylation reaction in molecular solvents led to mixtures of regioisomers under similar conditions. Several lines of evidence point to the unique regiocontrol stemming from the ionic environment provided by the ionic liquid that alters the reaction pathway. The chemistry provides a simple, effective method for preparing branched, arylated olefins and contributes to the extension of Heck reaction to a wider range of substrates.
- Mo, Jun,Xu, Lijin,Xiao, Jianliang
-
p. 751 - 760
(2007/10/03)
-
- Palladium-catalyzed regioselective Heck arylation of electron-rich olefins in a molecular solvent-ionic liquid cocktail
-
We have recently established that highly regioselective Heck arylation of electron-rich olefins can be accomplished with aryl halides without using any halide scavengers in imidazolium ionic liquid solvents. The results presented in this paper show that the benchmark electron-rich olefins vinyl ethers can be readily arylated by aryl bromides in a molecular solvent-ionic liquid cocktail with no compromise on regioselectivity. By introducing a small amount of 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) to DMSO, the arylation reactions of the vinyl ethers 1a-d by the bromides 2a-j took place to afford essentially only the α arylated products. The enamide 1e underwent similar regioselective arylation in the solvent cocktail. In the absence of the ionic liquid, lower regioselectivities were observed. In comparison with the chemistry we have reported so far, the current method reduces considerably the reliance on the volume of ionic liquids used, providing a simpler and more practical synthetic pathway for preparing arylated vinyl ethers and aryl methyl ketones.
- Mo, Jun,Liu, Shifang,Xiao, Jianliang
-
p. 9902 - 9907
(2007/10/03)
-
- Selective electrochemical aromatic fluorination of acetophenone and benzophenone
-
Electrochemical fluorination of acetofenone and benzophenone was studied in anhydrous HF and in solutions. The electrochemical fluorination of acetophenone in HF occurred exclusively in the ring and furnished ortho- and meta-isomers of fluoroacetophenone,
- Shainyan,Danilevich,Grigor'eva,Chuvashev
-
p. 1581 - 1586
(2007/10/03)
-
- Preparation process of fluorine substituted aromatic compound
-
A preparation process of a fluorine substituted aromatic compound comprising reacting an alkali metal or alkali earth metal salt of an aromatic compound having a hydroxy group with an organic fluorinating agent is disclosed. As a representative fluorinating agent, a bis-dialkylamino-difluoromethane compound, for example, 2,2′-difluoro-1,3-dimethylimidazolidine, is exemplified. According to the process, an industrially useful fluorinated aromatic compound, for example, a fluorobenzene, a fluorine substituted benzophenone, a fluorine substituted diarylsulfone can be prepared with ease in economy without specific equipment.
- -
-
-
- Propenoic acid derivatives diazole propenoic acid compounds which have useful pharmaceutical utility
-
A novel propenoic acid derivative which exhibits adenosine A1 antagonism is defined by the general formula (I): STR1 (wherein A represents an aromatic ring; R1 represents aryl or the like; R2, R3 and R4 each represent hydrogen, lower alkyl or the like; and R7 and R8 each represent lower alkyl or the like) or a pharmacologically acceptable salt thereof.
- -
-
-
- Direct Formation of (Haloaryl)copper Nucleophiles from Haloiodobenzenes and Active Copper
-
(o-Halophenyl)-, (m-halophenyl)-, and (p-halophenyl)copper reagents have been formed in moderate to high yields at room temperature from active copper and the corresponding haloiodobenzenes.These reagents have been cross-coupled with a variety of alkyl and acyl halides to produce the respective haloarenes and haloaryl ketones.Remarkably, (o-fluorophenyl)- and (o-chlorophenyl)copper are produced in good yields by this procedure without undergoing elimination to form benzyne making this approach a convenient method for generating o-halophenyl nucleophiles.
- Ebert, Greg W.,Pfennig, Deborah R.,Suchan, Scott D.,Donovan, Thomas A.,Aouad, Emmanuel,et al.
-
p. 2361 - 2364
(2007/10/02)
-
- UNE VOIE ORIGINALE ET SELECTIVE DE FONCTIONNALISATION EN POSITION META DU FLUORO- ET DE L'ETHYLBENZENE
-
An original and regioselective method for the meta functionalisation of fluoro- and ethylbenze is reported.This process involves a 2,5-disilylation of these subtrates using trimethylchlorosilane in the presence of lithium in THF as the solvent.After aromatisation, monodesilylation in position 2- and electrophilic substitution of the trimethylsilyl group in position 5-, meta acetyl-, senecioyl-, benzoyl-, and iodofluorobenzenes and ethylbenzenes as well as the sodium salts of metafluoro or meta ethylbenzenesulfonic acid and 3-aminosulfonylfluorobenzene were obtained in good yields. pair of diastereomeric triamines 15 and 16.A tricyclic diazasystem 19 was formed from the reaction of cyanide with the carbamoylated chloroenamine 18.Monochloroenamine 10a and dichloroenamine 12a showed a significant mutagenic behaviour in the Ames test.
- Bennetau, Bernhard,Krempp, Michele,Dunogues, Jacques,Ratton, Serge
-
p. 8131 - 8142
(2007/10/02)
-
- Production of m-fluoroacetophenone
-
A process for the production of m-fluoroacetophenone comprises reacting m-aminoacetophenone with a diazotization agent in the presence of hydrogen fluoride. The diazonium fluoride compound produced is decomposed by heating to produce highly pure m-fluoroacetophenone in good yields.
- -
-
-
- New Method for Selective Monofluorination of Aromatics Using Silver Difluoride
-
Fluorobenzene is obtained in 61percent yield from reaction of a solution of benzene in n-hexane with solid argentic fluoride (AgF2).The AgF2 acts as both a strong oxidant and the fluoride source.Cobaltic fluoride provides only low (8percent) yields of fluorobenzene under similar conditions.The predominant reaction of benzene solutions with AgF2 appears to proceed by a process involving initial electrophilic oxidative cis addition of two fluorine atoms from the solid AgF2 lattice to the para aromatic positions, leading to cis-3,6-difluoro-1,4-cyclohexadiene (F2CHD).The reductive elimination leaves solid argentous fluoride (AgF) which is easily recoverable by filtration.Elimination of HF from the F2CHD yields fluorobenzene.Reactions of haloaromatics with AgF2 generally proceed in a similar manner.Thus, further reaction of AgF2 with benzene or monohalo- or p-dihalobenzenes leads in steps to 3,3,6,6-tetrafluoro-1,4-cyclohexadiene (F4CHD) in up to 82percent yield.The modest to high yields of mono- and specific polyfluorinated aromatics contrast sharply with reported nonselective perfluorination in vapor-phase reactions of aromatics over AgF2 or CoF3.Reactions of AgF2 or CoF3 with solutions of nitrobenzene, acetophenone, benzoic acid, and benzonitrile give mixtures of o-, m-, and p-monofluoro derivatives.
- Zweig, Arnold,Fischer, Robert G.,Lancaster, John E.
-
p. 3597 - 3603
(2007/10/02)
-