Regio- and Stereoselective Conjugate Addition of Aldehydes to β-Tosyl Enones under the Catalysis of a Binaphthyl-Modified Chiral Amine

A simple axially chiral amine catalyst promoted the regio-, diastereo-, and enantioselective conjugate addition of aldehydes to beta-tosyl enones, which serve as ynone surrogates. The adducts were readily converted by treatment with L-selectride into less accessible enones with a gamma stereogenic center. Such compounds cannot be prepared through the amine-catalyzed conjugate addition of aldehydes to ynones. The obtained enones underwent further conjugate addition of diorganozinc compounds in the presence of a copper catalyst.