Ruthenium-Catalyzed Silyl Ether Formation and Enyne Metathesis Sequence:  Synthesis of Siloxacycles from Terminal Alkenyl Alcohols and Alkynylsilanes

Two consecutive ruthenium-catalyzed reactions have been achieved for the synthesis of siloxacycles from terminal alkenyl carbenols and alkynylsilanes. The metal-catalyzed dehydrogenative condensation between alcohols and silanes, generating molecular hydrogen as the only byproduct, allows for the subsequent enyne metathesis without isolating the intermediate silyl ethers. This system provides a streamlined synthesis of synthetically useful building blocks. [reaction: see text]