A two-step synthesis of α-keto vinyl carbinols from ketones.

Conjugate addition of lithium enolates onto terminal alkynyl- and allenyl-sulfoxides furnishes the corresponding allylic sulfoxides. The latter readily undergo a Mislow-Braverman-Evans rearrangement to yield the targeted α-keto vinyl carbinols. This two-step procedure does not require purification of the intermediates and constitutes the shortest approach to α-keto vinyl carbinols.