Unexpected C-C bond cleavage of epoxide motif: Rhodium(I)-catalyzed tandem heterocyclization/[4+1] cycloaddition of 1-(1-alkynyl)oxiranyl ketones

A rhodium(I)-catalyzed tandem heterocyclization and formal [4+1] cycloaddition of 1-(1-alkynyl)oxiranyl ketones was developed, which provides a general, efficient and practical route to highly substituted furo[3,4-b]furan-3(2H)-ones, wherein the epoxide motif undergo unexpected C-C bond cleavage rather than the classical C-O bond cleavage.