The organobase-mediated diastereoselective spirocyclopropanation of barbiturate-based olefins with 2,4-disubstituted benzyl chlorides has been developed. The reactions were carried out efficiently to afford the desired spirobarbiturate-cyclopropanes in up to 95% yield with more than 20:1 dr in favor of anti-isomers. In order to extend synthetic utility of the spiro-products, a Lewis acid induced cyclopropane-ring-expansion isomerization was also demonstrated.
Key words
spirobarbiturate-cyclopropane - spirocyclopropanation - barbiturate-based olefin - benzyl chloride - diastereoselective - synthetic methodology - organobase