TRANSITION-METAL-CATALYZED ASYMMETRIC VINYLCYCLOPROPANE-CYCLOPENTENE REARRANGEMENTS - ASYMMETRIC-SYNTHESIS OF CYCLOPENTANE DERIVATIVES USING CHIRAL SULFOXIDES AS CHIRAL SOURCES

Optically active alpha-olefinic cyclopropane derivatives, prepared by Michael addition of sodium bromomalonate to chiral vinylic sulfoxides followed by intramolecular asymmetric alkylation, led to facile transformation into chiral cyclopentane derivatives upon treatment with transition metals such as palladium, nickel, and platinum. The stereospecificity of the rearrangements was dependent on the catalysts and the reaction conditions employed. The palladium catalysts represented the highest stereospecificity.