Asymmetric total synthesis of (+)-aphanamol I based on the transition metal catalyzed [5 + 2] cycloaddition of allenes and vinylcyclopropanes

A concise asymmetric total synthesis of (+)-aphanamol I is described, based on the transition metal catalyzed 5 + 2] allenyl-vinylcyclopropane cycloaddition. The key cycloaddition precursor is convergently assembled from (R)-(+)-limonene and cyclopropane diester through a novel decarboxylative dehydration reaction. The metal-catalyzed 5 + 2] cycloaddition of this precursor proceeds with complete chemo, endo/exo, and diastereoselectivity in 93% yield, representing an effective general route to bicyclo5.3.0]decane derivatives.