Catalyst-Free Synthesis of Skipped Dienes from Phosphorus Ylides, Allylic Carbonates, and Aldehydes via a One-Pot SN2′ Allylation—Wittig Strategy.

The regioselective title reaction of stabilized phosphorus ylides with aliphatic and aromatic aldehydes as well as in situ generated ketenes [from (XV)] affords highly functionalized skipped dienes and synthetically important homoallylic allenoates with flexible substitution pattern.