Metal-Free Tunable 1,2-Difunctionalization of Terminal Alkynes: Synthesis of β-Substituted α,β-Unsaturated Ketones.

A metal-free tunable 1,2-difunctionalization of the terminal alkynes showcasing a tandem installation of C-C and C-S bonds has been developed. The key enabling factor for the approach is the use of acetic acid as an acyl source to synthesize β-substituted α,β-unsaturated ketones. The reaction at room temperature leads to the regioselective acylation at the terminal carbon of alkynes, whereas at -78 °C, the acylation occurs at the more substituted carbon.