F<sup>–</sup>-Free Deoxyhydrotrifluoromethylation of α-Keto Esters with Ph<sub>3</sub>P<sup>+</sup>CF<sub>2</sub>CO<sub>2</sub><sup>–</sup>: Synthesis of α–CF<sub>3</sub>-Substituted Esters
作者:Ying Zheng、Yimin Jia、Yuan Yuan、Zhong-Xing Jiang、Zhigang Yang
DOI:10.1021/acs.joc.0c01518
日期:2020.8.21
direct deoxyhydrotrifluoromethylation of α-keto esters with a difluoromethylating reagent has been achieved, in which the employment of water can promote the dissociation of the CF2 group to form a CF3 moiety, which provides the successful transformation. The current protocol demonstrates one of the most practical approaches to generate α-trifluoromethyl esters with a broad substrate scope and high functional
The asymmetric construction of quaternarycarboncentersviacross-aldolreactions of ketones with β,γ-unsaturated keto esters catalyzed by 4-(tert-butyldiphenylsilyloxy)-pyrrolidine-2-carboxylic acid in water is described. The adducts bearing two adjacent chiral centers were obtained in high yields, mostly up to 99% ee, and with high diastereoselectivities. The corresponding polyfunctional products
The asymmetric Cu(<scp>ii</scp>)–indolinylmethanol complex catalyzed Diels–Alder reaction of 2-vinylindoles with β,γ-unsaturated α-ketoesters: an efficient route to functionalized tetrahydrocarbazoles
作者:Banlai Ouyang、Tingting Yu、Renshi Luo、Gui Lu
DOI:10.1039/c4ob00196f
日期:——
An efficient asymmetric Diels–Alder reaction of 2-vinylindoles with β,γ-unsaturatedα-ketoesters has been developed for the construction of functionalized tetrahydrocarbazoles. The products were obtained in high yields (up to 96%) with good stereoselectivities (ee up to 95%, dr up to >99 : 1).
Preparation of enantiomerically pure (3E)-alkyl-4-(hetero-2-yl)-2-hydroxybut-3-enoates by Candida parapsilosis ATCC 7330 mediated deracemisation and determination of the absolute configuration of (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate
作者:T. Vaijayanthi、Anju Chadha
DOI:10.1016/j.tetasy.2007.04.029
日期:2007.5
enoates using Candida parapsilosis ATCC 7330 resulted in the formation of one enantiomer in high enantiomeric excess [up to >99% ee] and isolated yields [up to 79%]. The absolute configuration of the enantiomerically pure (3E)-ethyl-4-(thiophene-2-yl)-2-hydroxybut-3-enoate as determined by 1H NMR of the Mosher esters was found to be (S).
使用假丝酵母假丝酵母ATCC 7330对消旋的(3 E)-烷基-4-(杂-2-基)-2-羟基丁-3-烯酸酯进行消旋,导致形成一种对映体,其对映体过量高[ee高达> 99% ]和孤立的收率[高达79%]。通过Mosher酯的1 H NMR测定,发现对映体纯的(3 E)-乙基-4-(噻吩-2-基)-2-羟基丁-3-烯酸酯的绝对构型为(S)。
Highly Enantioselective Reactions of Cyclohexanone and<i>β</i>,<i>γ</i>-Unsaturated<i>α</i>-Keto Ester: The Tuning of Chemo-selectivities by Secondary and Primary Amine Catalysts
作者:Jianwei Wei、Wengang Guo、Xin Zhou、Xin Du、Yan Liu、Can Li
DOI:10.1002/cjoc.201400431
日期:2014.10
amphiphilic imidazole based secondary and primaryaminecatalysts were synthesized and shown to be very effective with an acid cocatalyst for the asymmetric reaction of cyclohexanone to β,γ‐unsaturated α‐keto ester. Interestingly, primary and secondaryaminecatalysts show different regio‐selectivities in this reaction. Under the catalysis of secondaryamine 1, excellent enantioselectivities were observed for