configurations of a series of primary alcohols possessing a branched methylgroup at C2 position were examined on the basis of a modified Mosher's method proposed by Minale et al. It was revealed that in many cases the absolute configurations at C2 were assignable from the chemicalshift differences of geminal protons of the methylene attached to the ester linkage in the alpha-methoxy-alpha-trifluoromethylphenylacetyl
Deaminative Borylation of Aliphatic Amines Enabled by Visible Light Excitation of an Electron Donor-Acceptor Complex
作者:Frederik Sandfort、Felix Strieth-Kalthoff、Felix J. R. Klauck、Michael J. James、Frank Glorius
DOI:10.1002/chem.201804246
日期:2018.11.22
strategy for the borylation of aliphatic primary amines is described. Alkyl radicals derived from the single‐electron reduction of redox‐active pyridinium salts, which can be isolated or generated in situ, were borylated in a visible light‐mediated reaction with bis(catecholato)diboron. No catalyst or further additives were required. The key electron donor–acceptor complex was characterized in detail
Stereoconvergent preparation of chiral vinylsilanes by cuprate substitution of α-acetoxyallylsilanes. Application to the synthesis of ( S )-(+)-bishomomanicone
作者:Boris Guintchin、Stefan Bienz
DOI:10.1016/s0040-4020(03)01169-4
日期:2003.9
Enantiomerically enriched (E)- and (Z)-configured α-acetoxyallylsilanes have been prepared starting from a chiral acylsilane bearing an asymmetric unit at the silicon portion. Treatment of these compounds with organocuprates afforded the respective vinylogous substitution products in high yields and high stereoselectivities. The transformations proceed essentially by complete anti attack of the nucleophiles