A Divergent Enantioselective Strategy for the Synthesis of Griseusins

Abstract

AbstractThe first enantioselective total synthesis of griseusin A, griseusin C, 4′‐deacetyl‐griseusin A, and two non‐native counterparts in 11–14 steps is reported. This strategy highlights a key hydroxy‐directed CH olefination of 1‐methylene isochroman with an α,β‐unsaturated ketone followed by subsequent stereoselective epoxidation and regioselective cyclization to afford the signature tetrahydro‐spiropyran ring. Colorectal cancer cell cytotoxicities of the final products highlight the impact of the griseusin tetrahydro‐spiropyran ring on bioactivity. As the first divergent enantioselective synthesis, the strategy put forth sets the stage for further griseusin mechanism‐of‐action and SAR studies.