Synthesis of optically enriched spirocyclic benzofuran-2-ones by bifunctional thiourea-base catalyzed double-Michael addition of benzofuran-2-ones to dienones.

A highly enantioselective catalytic double-Michael addition reaction of substituted benzofuran-2-ones with divinyl ketones promoted by readily accessible tertiary amine-thiourea Cinchona alkaloids has been developed. A number of optically enriched spirocyclic benzofuran-2-ones were prepared in very good yields (up to 99 %), diastereoselectivities (up to 19… CONTINUE READING