A Unified Synthesis of Electron-Deficient 1,4- and 1,1,4-Substituted 1,3-Dienes through a Base-Promoted Allylation Followed by Retro-Michael Vinylogous Dehydrosulfinylation

We disclose a general 2-step synthesis of electron-poor 1,4- and 1,1,4-substituted buta-1,3-dienes bearing electron-withdrawing substituents at both termini of the conjugated system. The method relies on a base-promoted C-allylation of primary or secondary alkylsulfones with γ-bromocrotonate or related amide, nitrile, or sulfone and subsequent vinylogous