A New Protocol for the In Situ Generation of Aromatic, Heteroaromatic, and Unsaturated Diazo Compounds and Its Application in Catalytic and Asymmetric Epoxidation of Carbonyl Compounds. Extensive Studies To Map Out Scope and Limitations, and Rationalization of Diastereo- and Enantioselectivities
作者:Varinder K. Aggarwal、Emma Alonso、Imhyuck Bae、George Hynd、Kevin M. Lydon、Matthew J. Palmer、Mamta Patel、Marina Porcelloni、Jeffery Richardson、Rachel A. Stenson、John R. Studley、Jean-Luc Vasse、Caroline L. Winn
DOI:10.1021/ja034606+
日期:2003.9.1
a general process for the in situ generation of diazo compounds from tosylhydrazone sodium salts has been established and applied in sulfur-ylide mediated epoxidation reactions. The chiral, camphor-derived, [2.2.1] bicyclic sulfide 7 was employed (at 5-20 mol % loading) to render the above processes asymmetric with a range of carbonyl compounds and tosylhydrazone sodium salts. Benzaldehyde tosylhydrazone
Synthesis of Epoxides from Alkyl Bromides and Alcohols with in Situ Generation of Dimethyl Sulfonium Ylide in DMSO Oxidations
作者:Zhi-Wei Zhang、Hai-Bo Li、Jin Li、Cui-Cui Wang、Juan Feng、Yi-Hua Yang、Shouxin Liu
DOI:10.1021/acs.joc.9b02621
日期:2020.1.17
the readily available alkyl bromides and alcohols to value-added epoxides using dimethyl sulfoxide (DMSO) under mild reaction conditions has been developed. Benzyl and allyl bromides, and activated and unactivated alcohols all proceeded smoothly to give epoxides in high to excellent yield. Dimethyl sulfide, generated by DMSO oxidations, was in situ elaborated to form the substituted dimethyl sulfonium
DNA-based hydrolytic kinetic resolution of epoxides
作者:Ewold W. Dijk、Ben L. Feringa、Gerard Roelfes
DOI:10.1016/j.tetasy.2008.10.004
日期:2008.10
DNA-bound copper(H) complexes serve as catalysts for the hydrolytic kinetic resolution of 2-pyridyloxiranes in water. Selectivity factors of up to 2.7 were achieved, indicating a chirality transfer of DNA to epoxides via a coordinated metal ion. (C) 2008 Elsevier Ltd. All rights reserved.
The chemistry of oxiranyl remote anions derived from α,β-epoxypyridines is investigated. Deprotonation of α,β-epoxy pyridines at the β-position and reactions of the corresponding anions with a variety of electrophiles are found to be highly regioselective, possibly as a consequence of stabilization from the chelation between lithium and the pyridine moiety in the form of a five-membered cyclic intermediate