Acid-catalyzed direct conjugate alkenylation of α,β-unsaturated ketones

Abstract

New tricks, old reaction: The title reaction proceeds under mild and transition-metal-free conditions (see scheme; Tf=trifluoromethanesulfonyl). Various combinations of substrates are applicable to the synthesis of γ,δ-unsaturated ketones by employing silicon substituents at the β-position of the enones. The silicon substituents play a key role in stabilization of the cationic intermediate by hyperconjugation.

Keywords: Lewis acid; conjugate addition; homogeneous catalysis; silicon; synthetic methods.