Non-Photochemical Synthesis of Condensed Cyclobutenes. Syntheses of the cis-anti-cis-Tricyclo(5.3.0.02,6)decane Skeleton.

Abstract The way to the cis-anti-cis tricyclo [5.3.0.0 2,6 ] decane skeleton which represents an important substructure of natural sesquiterpenes(bourbonenes) and natural diterpenes(spatanes) is described starting from functionalized bicyclo [3.2.0] heptanic derivatives.