Iridium-catalyzed enantioselective allylation of silyl enol ethers derived from ketones and α,β-unsaturated ketones.

The unified Ir-catalyzed enantioselective allylic substitution reactions of silyl enol ethers derived from ketones and α,β-unsaturated ketones with branched, racemic allylic alcohols are described. This transformation is catalyzed by the Carreira system and proceeds without fluoride, and with high ee and b : l ratio. The synthetic utility of this method was illustrated by the concise enantioselective total synthesis of marine natural products calyxolane A, B and by the assignment of the absolute configuration of calyxolane A.