Reaction of lithium diphenylphosphonium di(methylide) with carbonic acid derivatives. A novel access to polyfunctional unsaturated esters and amides

Abstract

AbstractThe lithium diphenylphosphonium di(methylide) Ph2 P(CH2)2 Li 1 readily attacks cyclic carbonates, carbamates, and thiocarbamates, resulting in “pseudo‐acylation” products, after a ring‐opening step. Thus, new stabilized ylides are prepared, which can be used in situ as carbonyl olefination reagents towards aldehydes. This procedure is a new one‐pot method for the synthesis of (E)‐vinylic esters and amides, bearing a free ω‐hydroxyl group. When a thiocarbamate is the initial substrate for 1, a Michael‐type cyclization occurs, following the Wittig olefination, resulting in the one‐pot preparation of 7‐membered heterocycles.