Ynamide Preactivation Allows a Regio- and Stereoselective Synthesis of α,β-Disubstituted Enamides.

A novel ynamide preactivation strategy enables the use of otherwise incompatible reagents and allows preparation of α,β-disubstituted enamides with high regio- and stereoselectivity. Mechanistic analysis reveals the intermediacy of a triflate-bound intermediate as a solution-stable, effective keteniminium reservoir, whilst still allowing subsequent addition of organometallic reagents.