Selective Reduction of α,β-Unsaturated Esters with NaBH4-BiCl3System
摘要:
Sodium borohydride-bismuth chloride system was applied for the selective reduction of carbon-carbon double bond of alpha,beta-unsaturated esters with high selectivity.
versions as electron-rich neutral stereodirecting ancillary ligands for enantioselective transformations. Herein we demonstrate that cyclic (alkyl)(amino)carbene (CAAC) ligands can also engage in asymmetric transformations, thereby expanding the toolbox of available chiral carbenes.
Chiral Ugi-Type Amines: Practical Synthesis, Ligand Development, and Asymmetric Catalysis
作者:Wu-Wei Dong、Yi-Nan Li、Xin Chang、Chong Shen、Chun-Jiang Wang
DOI:10.1021/acscatal.0c04077
日期:2020.11.6
privileged chiral skeleton for chiralligand design bearing central/planar chirality, and such ligands have exhibited tremendous success in various asymmetriccatalysis. However, the current access to enantiopure Ugi’s amine is quite tedious and relies heavily on optical resolution, which impedes its practical applications, to some extent. Herein, we present a facile asymmetricsynthesis of enantioenriched
Reactions de wittig-horner et de transesterification en une operation par activation anionique de liaisons C-H et O-H en milieu heterogene carbonate de potassium/alcool
作者:Z. Mouloungui、R. Elmestour、M. Delmas、A. Gaset
DOI:10.1016/s0040-4020(01)90785-9
日期:1992.1
The Wittig-Horner reaction carried out in various alcohols is accompanied by transesterification of the alkyl radical of the α, β-ethylenic ester formed. The occurrence of these two reactions in the same reaction medium is affected by the behavior of: i) the alcohol (solvent and reagent), ii) potassium carbonate (reagent and catalyst). The propensity for the two reactions to occur was found to depend
TMSCl-Mediated Catalytic Carbocupration of Alkynoates: An Unprecedented and Remarkable Effect of Catalyst Loading on Highly Selective Stereochemical Induction via a TMS-Allenoate Intermediate
New solid-supported phosphonate reagents for the synthesis of Z-α,β-unsaturated esters
作者:Sébastien L.X. Martina、Richard J.K. Taylor
DOI:10.1016/j.tetlet.2004.02.138
日期:2004.4
Novel solid-supported phosphonate reagents have been prepared and evaluated for the synthesis of α,β-unsaturated esters with a preference for the Z-alkene. The optimal reagent was a hybrid of both Still–Gennari and Ando reagents, and showed good to high yields and fair to good Z-selectivity for the conversion of both aliphatic and aromatic aldehydes.