Synthesis of α-alkenyl-β-hydroxy adducts by α-addition of unprotected 4-bromocrotonic acid and amides with aldehydes and ketones by chromium(II)-mediated reactions
作者:Ludger A. Wessjohann、Harry Wild、Leonildo A. Ferreira、Henri S. Schrekker
regio-, diastereo-, and enantiocontrolled access to alpha,beta-unsaturated delta-lactones is described, based on the reaction of a silyl dienolate and an aldehyde in the presence of 10 % of Carreira's catalyst. The scope and limitations of this reaction, as well as mechanisticinsights concerning the reactivity of an allyl copper species, are discussed.
Regioselective control of allyl anions with cadmium chloride: α γ condensation with aldehydes
作者:Lei Bo、Alex G Fallis
DOI:10.1016/s0040-4039(00)85166-7
日期:1986.1
A general method for directing the condensation of allyl anions such as with aldehydes preferentially to the γ position of the unsaturated nucleophile is described. The procedure employs cadmium chloride to control the regioselectivity and will facilitate the extended use of vinylogous anions in synthesis.