Enantioselective direct vinylogous aldol-cyclization cascade reaction between β,γ-unsaturated amides and o-quinones

Abstract

1,2-Diketones are employed, for the first time, as electrophiles in the vinylogous aldol reaction. With 5 mol% of chiral tertiary amine-thiourea C8, a direct vinylogous aldol-cyclization cascade reaction between β,γ-unsaturated amides and o-quinones has been achieved to produce spirocyclic dihydropyranones in 76–99% yield and 82–95% ee.