Efficient Construction of the Bicyclo[5.3.0]decenone Skeleton Based on the Rh(I)-Catalyzed Allenic Pauson−Khand Reaction

A reliable procedure for constructing a bicyclo[5.3.0]deca-1,7-dien-9-one ring system by rhodium-catalyzed Pauson−Khand reaction (PKR) of allenynes with a sulfonyl group has been developed. Investigation of the rhodium-catalyzed PKR on 19 examples of 1,2-nonadien-8-yne derivatives demonstrated that (i) acceptable yields could be consistently achieved through the proper choice of the rhodium catalyst ([RhCl(CO)₂]₂ or [RhCl(CO)dppp]₂) depending on the starting allenyne and that (ii) an ester functionality as well as hydroxy and siloxy groups could be tolerated in this rhodium-catalyzed PKR.