Rhodium-Catalyzed [5 + 2] Cycloadditions of Allenes and Vinylcyclopropanes: Asymmetric Total Synthesis of (+)-Dictamnol

The asymmetric synthesis of (+)-dictamnol is described, based on the rhodium catalyzed [5 + 2] cycloaddition of an allene and vinylcyclopropane. This cycloaddition methodology provides the basis for a general and efficient route to various bicyclo[5.3.0]decenes, ring systems common to a wide range of natural and designed compounds of structural and medicinal interest.