Platinum-Catalyzed Hydrative Dimerization of Alkynylsilanes to α,β-Unsaturated Ketones

A unique type of platinum catalysis that is valuable for the synthesis of α,β-unsaturated ketones is described. In the presence of PtCl2, (2-arylethynyl)­trimethylsilanes reacted with H2O at 30 °C to give 1,4-diarylbut-3-en-2-ones in moderate to good yields. (2-Alkylethynyl)­trimethylsilanes could be efficiently converted into the corresponding hydrative dimerization products by a modified Pt catalyst system. Mechanistic studies suggest the participation of acylplatinum intermediates in the catalytic cycle.