Ruthenium-catalyzed dienyne formation from propargylic alcohols and 1,3-conjugated dienes

Ruthenium-catalyzed carbon-carbon bond forming reactions between propargylic alcohols and acyclic and cyclic 1,3-conjugated dienes give the corresponding dienyne compounds in good to high yields. Only the use of thiolate-bridged diruthenium complexes promotes the catalytic reactions, where a ruthenium-alkynyl complex, a resonance structure of a ruthenium-allenylidene complex, works as a key intermediate. This carbon-carbon bond forming reaction is considered to proceed via a stepwise reaction pathway. The finding described in this article reveals another novel catalytic reactivity of chalcogenolate-bridged diruthenium complexes.