- Development of a Modified Bouveault-Blanc Reduction for the Selective Synthesis of α,α-Dideuterio Alcohols
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A modified Bouveault-Blanc reduction has been developed for the synthesis of α,α-dideuterio alcohols from carboxylic acid esters. Sodium dispersions are used as the electron donor in this electron transfer reaction, and ethanol-d1 is employed a
- Han, Minhui,Ma, Xiaodong,Yao, Shangchu,Ding, Yuxuan,Yan, Zihan,Adijiang, Adila,Wu, Yufei,Li, Hengzhao,Zhang, Yuntong,Lei, Peng,Ling, Yun,An, Jie
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Read Online
- Acyl fluorides as direct precursors to fluoride ketyl radicals: Reductive deuteration using SmI2and D2O
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A highly chemoselective reductive deuteration of acyl fluorides to provide α,α-dideuterio alcohols with exquisite levels of deuterium incorporation was developed using SmI2 and D2O as the deuterium source. This method introduces acyl fluorides as attracti
- Li, Hengzhao,Peng, Mengqi,Lai, Zemin,Ning, Lei,Chen, Xingyue,Zhang, Xiaoxu,Wang, Pengjie,Szostak, Roman,Szostak, Michal,An, Jie
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p. 5195 - 5198
(2021/05/31)
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- The invention relates to an acyl fluoride compound reduction and deuteration synthesis α, α - dideuterium alcohol. Method for deuterated drugs
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The invention relates to an α, α - dideuterium-substituted alcohol compound and a reduction deuteration method for preparing an acyl fluoride compound of α, α - dideuterium-substituted alcohol compounds, characterized in that α, α - dideuterium-substituted alcohol compounds represented by the general formula 2 (1) are reacted in an organic solvent I by a deuterium donor reagent. The method solves the problems that in the prior art α, α - dideuterium-substituted alcohol compounds are prepared by using inflammable reductant, poor selectivity and atomic economy, the invention establishes a method for reducing and deuteration of acyl fluoride compounds based on single electron transfer reduction deuteration reaction. The method can be used for preparing α, α - dideuterium-substituted alcohol compounds, and has the advantages of high product deuterium substitution rate, good regioselectivity, good chemical selectivity, low reagent price, simple operation, mild conditions and wide substrate application range.
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Paragraph 0038-0041
(2021/08/25)
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- Alpha, alpha-dideuterated alcohol compound and preparation method thereof
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The invention relates to a method for synthesizing an alpha, alpha-dideuterated alcohol compound shown in a general formula (2), which is characterized in that an amide compound shown in a general formula (1) reacts with a bivalent lanthanide transition metal compound, a deuterium donor reagent and Lewis base in an organic solvent I to generate the alpha, alpha-dideuterated alcohol compound shown in the general formula (2) . compared with the traditional method, the method has the advantages of strong selectivity, high yield, high deuteration rate, few toxic and side products, low cost, mild reaction conditions, simplicity in operation, environmental friendliness and the like.
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Paragraph 0018-0021
(2021/04/21)
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- A trinuclear chromium(iii) chlorocarbyne
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Reduction of CCl4 by CrCl2 in THF afforded a trinuclear chromium(iii) carbyne [CrCl(thf)2]3(μ3-CCl)(μ-Cl)3. The chlorocarbyne complex reacted with aldehydes to afford chloroallylic alcohols and terminal alkynes. The mechanistic study proposed two competitive pathways via an α-chlorovinyl intermediate.
- Kurogi, Takashi,Irifune, Keiichi,Enoki, Takahiro,Takai, Kazuhiko
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p. 5199 - 5202
(2021/05/31)
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- Pentafluorophenyl Esters: Highly Chemoselective Ketyl Precursors for the Synthesis of α,α-Dideuterio Alcohols Using SmI2 and D2O as a Deuterium Source
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We report the first highly chemoselective synthesis of α,α-dideuterio alcohols with exquisite incorporation of deuterium (>98% [D2]) using pentafluorophenyl esters as ketyl radical precursors, SmI2 as a mild reducing agent, and Dsub
- Li, Hengzhao,Hou, Yuxia,Liu, Chengwei,Lai, Zemin,Ning, Lei,Szostak, Roman,Szostak, Michal,An, Jie
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p. 1249 - 1253
(2020/01/31)
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- Method used for reduction of tertiary amide into alcohols and/or amines
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The invention discloses a method used for reduction of tertiary amide into alcohols and/or amines. The method comprises following steps: tertiary amide, an alkali metal reagent, and a proton donor agent are added into an organic solvent for a following reaction selectively: when the proton donor agent is a raw material alcohol and/or inorganic salt aqueous solution, the reaction product is an alcohol compound and/or tertiary amine compound. The method is capable of realizing selective reduction of tertiary amide into alcohols and tertiary amine compounds, the yield is high, the suitable rangeis wide, operation is safe and simple, the adopted raw materials are cheap and easily available; no precious metal catalyst, toxic silanes, and flammable and combustible metal hydrides are adopted; notoxic by product is generated; reaction is more friendly to the environment; problems in the prior art that amide compound reducing method operation is complex, conditions are strict, and control ofproducts is difficult are solved.
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Paragraph 0079-0082
(2019/08/07)
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- Vicinal Diboration of Alkyl Bromides via Tandem Catalysis
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Vicinal diboration of alkyl bromides via tandem catalysis is reported. The reported reaction exhibits a broad substrate scope, good functional group compatibility, and regioselectivity. Moreover, it shows good practicality due to the easy accessibility of alkyl bromides in combination with diverse transformations of diboronates. Mechanism study indicates that terminal alkenes are generated selectively through nickel-catalyzed dehydrohalogenation of alkyl bromides followed by base/MeOH promoted diboration process to provide 1,2-diboration products.
- Wang, Xiao-Xu,Li, Lei,Gong, Tian-Jun,Xiao, Bin,Lu, Xi,Fu, Yao
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supporting information
p. 4298 - 4302
(2019/06/14)
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- Reduction and Reductive Deuteration of Tertiary Amides Mediated by Sodium Dispersions with Distinct Proton Donor-Dependent Chemoselectivity
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A practical and scalable single electron transfer reduction mediated by sodium dispersions has been developed for the reduction and reductive deuteration of tertiary amides. The chemoselectivity of this method highly depends on the nature of the proton donor. The challenging reduction via C-N bond cleavage has been achieved using Na/EtOH, affording alcohol products, while the use of Na/NaOH/H2O leads to the formation of amines via selective C-O scission. Sodium dispersions with high specific surface areas are crucial to obtain high yields and good chemoselectivity. This new method tolerates a range of tertiary amides. Moreover, the corresponding reductive deuterations mediated by Na/EtOD-d1 and Na/NaOH/D2O afford useful α,α-dideuterio alcohols and α,α-dideuterio amines with an excellent deuterium content.
- Zhang, Bin,Li, Hengzhao,Ding, Yuxuan,Yan, Yuhao,An, Jie
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p. 6006 - 6014
(2018/05/24)
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- Synthesis method of alpha,alpha-dideuterated alcohol compound
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The invention belongs to the field of organic synthesis, and relates to a synthesis method of an alpha,alpha-dideuterated alcohol compound. The synthesis method is selected from the following methods including an alkali metal-mediated single electron tran
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Paragraph 0075; 0076; 0077; 0078
(2018/04/01)
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- Alkene migration to the end-terminal carbon bearing a phenyl group over a chiral siloxy carbon center in Heck reaction
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Abstract The Heck reaction of aryl bromide with a terminal alkene substrate having a chiral center at the allylic position and a phenyl substituent at another terminal carbon is reported. An alkene migration to the phenyl-substituted end carbon is observed, along with the typical Heck reaction. This zipper-type migration occurs through multiple internal carbon bonds, and the stereochemistry of the internal chiral center is completely retained during this process.
- Ida, Akiko,Hoshiya, Naoyuki,Uenishi, Jun'ichi
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supporting information
p. 6442 - 6448
(2015/08/18)
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- Selective synthesis of α,α-dideuterio alcohols by the reduction of carboxylic acids using Smi2 and D2O as deuterium source under set conditions
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The first general method for the chemoselective synthesis of α,α-dideuterio alcohols directly from feedstock carboxylic acids under single electron transfer conditions using SmI2 is reported. This reaction proceeds after the activation of Sm(II
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information
p. 5052 - 5055
(2014/12/11)
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- Highly chemoselective reduction of amides (primary, secondary, tertiary) to alcohols using SmI2/amine/H2O under mild conditions
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Highly chemoselective direct reduction of primary, secondary, and tertiary amides to alcohols using SmI2/amine/H2O is reported. The reaction proceeds with C-N bond cleavage in the carbinolamine intermediate, shows excellent functional group tolerance, and delivers the alcohol products in very high yields. The expected C-O cleavage products are not formed under the reaction conditions. The observed reactivity is opposite to the electrophilicity of polar carbonyl groups resulting from the nX → πC=O (X = O, N) conjugation. Mechanistic studies suggest that coordination of Sm to the carbonyl and then to Lewis basic nitrogen in the tetrahedral intermediate facilitate electron transfer and control the selectivity of the C-N/C-O cleavage. Notably, the method provides direct access to acyl-type radicals from unactivated amides under mild electron transfer conditions.
- Szostak, Michal,Spain, Malcolm,Eberhart, Andrew J.,Procter, David J.
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supporting information
p. 2268 - 2271
(2014/03/21)
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- Stereospecific asymmetric N-heterocyclic carbene (NHC)-catalyzed redox synthesis of trifluoromethyl dihydropyranones and mechanistic insights
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N-Heterocyclic carbene (NHC)-catalyzed redox asymmetric hetero-Diels-Alder reactions of α-aroyloxyaldehydes with β-trifluoromethyl enones generates synthetically useful dihydropyranones containing a stereogenic trifluoromethyl substituent in good yields (up to 81%) and excellent diastereoselectivity and enantioselectivity (up to >95:5 dr and >99% ee). The process is stereospecific, with use of either (E)- or (Z)-β- trifluoromethyl enones forming syn- or anti-dihydropyranone products, respectively. Mechanistic studies through in situ kinetic analysis of the reaction reveal key differences in reactivity between chiral NHC precursor 1 and an achiral NHC precursor.
- Davies, Alyn T.,Taylor, James E.,Douglas, James,Collett, Christopher J.,Morrill, Louis C.,Fallan, Charlene,Slawin, Alexandra M. Z.,Churchill, Gwydion,Smith, Andrew D.
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p. 9243 - 9257
(2013/10/08)
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- Electron transfer reduction of carboxylic acids using SmI 2-H2O-Et3N
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The first general method for efficient electron transfer reduction of carboxylic acids has been developed. The protocol using SmI2 - H 2O - Et3N allows for reduction of a variety of carboxylic acids in excellent yields and provides an attractive alternative to processes mediated by reactive alkali metals, lithium aluminum hydride, and boron hydrides. Of broader significance, the method allows acyl radical equivalents to be generated from carboxylic acids under mild reaction conditions.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information; experimental part
p. 840 - 843
(2012/04/11)
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- A small molecule that walks non-directionally along a track without external intervention
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Charge of the light brigade: A molecule is able to walk back and forth upon a five-foothold pentaethylenimine track without external intervention. The 1D random walk is highly processive (mean step number 530) and exchange takes place between adjacent amine groups in a stepwise fashion. The walker performs a simple task whilst walking: quenching of the fluorescence of an anthracene group sited at one end of the track. Copyright
- Campana, Araceli G.,Carlone, Armando,Chen, Kai,Dryden, David T. F.,Leigh, David A.,Lewandowska, Urszula,Mullen, Kathleen M.
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supporting information; experimental part
p. 5480 - 5483
(2012/07/14)
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- Electron transfer reduction of unactivated esters using SmI 2-H2O
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The reduction of unactivated esters using samarium diiodide is reported for the first time. The optimised protocol allows for the reduction of primary, secondary and tertiary alkyl esters in excellent yields and is competitive with reductions mediated by metal hydrides and alkali metals.
- Szostak, Michal,Spain, Malcolm,Procter, David J.
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supporting information; experimental part
p. 10254 - 10256
(2011/10/31)
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- A mechanistic study of the chromium(II)-mediated transformations of trichloromethyl alkyls and carbinols: evidence for carbene, carbyne, and carbenoid intermediates
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Using CrCl2 in THF at room temperature, trichloromethyl carbinols and trichloromethylalkanes are readily transformed to the highly reactive α-chlorocarbenes, carbynes and α-chloro-α-chromium(III) vinylidene carbenoids. A mechanistic study is carried out to determine the nature of the intermediates.
- Bejot, Romain,Tisserand, Steve,Li, De Run,Falck,Mioskowski, Charles
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p. 3855 - 3858
(2008/02/02)
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- Unexpected formation of aryl ketones by palladium-catalyzed coupling of aryl bromides with vinylic acetates
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A palladium-catalyzed coupling reaction of aryl bromides with vinylic acetates in the presence of tributyitin methoxide has been described. Unexpected formation of aryl ketones was obtained. Preliminary mechanistic studies indicated that the reaction proceeded by the addition of the aryl moiety in the coordination sphere of palladium to a ketene.
- Jean, Mickael,Renaulty, Jacques,Uriac, Philippe,Capet, Marc,Van De Weghe, Pierre
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p. 3623 - 3625
(2008/02/12)
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- Development of a catalytic asymmetric variant of Hoppe's O-alkyl carbamate deprotonation methodology
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The optimisation of a ligand-exchange approach to catalytic asymmetric deprotonation of O-alkyl carbamates and subsequent electrophilic trapping (the 'Hoppe reaction') is presented. The method uses s-BuLi and sub-stoichiometric amounts of a chiral diamine [(-)-sparteine or the (+)-sparteine surrogate] in conjunction with an achiral 'regenerating' diamine (bisisopropyl bispidine) for the deprotonation and proceeds with good yields (up to 84%) and high enantioselectivity (up to 94:6 er). The first applications of this catalytic asymmetric deprotonation methodology in natural product synthesis are also described. Georg Thieme Verlag Stuttgart.
- McGrath, Matthew J.,O'Brien, Peter
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p. 2233 - 2241
(2008/02/02)
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- Structure of the modified heme in allylbenzene-inactivated chloroperoxidase determined by Q-band CW and pulsed ENDOR
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During the epoxidation of allylbenzene, chloroperoxidase (CPO) is converted to an inactive green species in which the prosthetic heme has been modified by addition of the alkene plus an oxygen atom (Dexter, A. F.; Hager, L. P. J. Am. Chem. Soc. 1995, 117,
- Lee, Hong-In,Dexter, Annette F.,Fann, Yang-Cheng,Lakner, Frederick J.,Hager, Lowell P.,Hoffman, Brian M.
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p. 4059 - 4069
(2007/10/03)
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- Chemoselectivity in the ruthenium-catalyzed redox isomerization of allyl alcohols
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Adjustment of oxidation level by internal hydrogen reorganization represents a highly efficient synthetic protocol. Cyclopentadienylbis(triphenylphosphine)ruthenium chloride in the presence of triethylammonium hexafluorophosphate catalyzes the redox isomerization of allyl alcohols to their saturated aldehydes or ketones. High chemoselectivity is observed since simple primary and secondary alcohols and isolated double bonds are not affected by this catalyst. The reaction is sensitive to the degree of substitution on the double bond and requires relatively unhindered olefins. Switching to indenylbis(triphenylphosphine)ruthenium chloride in the presence of triethylammonium hexafluorophosphate significantly expands the scope of the reaction to substrates bearing more substituted olefinic linkages and to cyclic substrates of rings containing eight or more members. The mechanism is probed by deuterium labeling, which shows that the metal catalyzes an intramolecular 1,3-hydrogen shift of the carbinol hydrogen to the terminal olefinic position.
- Trost, Barry M.,Kulawiec, Robert J.
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p. 2027 - 2036
(2007/10/02)
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- Collision-induced Dissociations of Aryl-substituted Alkoxide Ions. Losses of Dihydrogen and Rearrangement Processes
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The ion PhCH2O- undergoes competitive losses of H., H2, CH2O, and C6H6 upon collisional activation.The loss of H2 occurs mainly to form (C6H4)-CHO, and ab initio calculations suggest the reaction proceeds by the stepwise m
- Raftery, Mark J.,Bowie, John H.,Sheldon, John C.
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p. 563 - 570
(2007/10/02)
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- Mechanistic Features of Allylic Hydrogen Abstraction by Alkoxy Radicals
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A TS(excit) of angular H abstraction from allylbenzene in the course of the allylic acetoxylation reaction was previously invoked to explain a temperature-independent primary KIE; kH/kD = 2.90.This reaction geometry is now fully supported by the finding of inverse α-secondary deuterium isotope effects at both ends of the double bond in allylbenzene; (kH/kD)αC1 = 0.977 and (kH/kD)αC2 = 0.985.In keeping with these results an unsymmetrically structured, bridged radical intermediate, formed by the interaction of t-BuO with the allylic double bond, steers the reaction course.Such a complex is recognized to be unusual since most of the verified cases of radical bridging involve heteroatom centers capable of octet expansion.A discussion is also given of the factors determining the relative influence of benzene and double bond participation in the H-abstraction reactions of allylbenzene, which possesses both of these activating functions.
- Kwart, H.,Brechbiel, M.,Miles, W.,Kwart, L.D.
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p. 4524 - 4528
(2007/10/02)
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