Stereoselective syntheses of piperidinones and their modification by organometallic coupling reactions

Abstract

Dehydropiperidinones stereoselectively obtained from N-arabinosyl imines were iodinated at the enaminone structure. Knochel iodine–magnesium exchange afforded Grignard compounds of these piperidinone derivatives which reacted, either directly or after transmetalation to zinc or copper intermediates, with alkyl-, aryl- or acylhalides to give correspondingly substituted piperidinones. Stereoselective conjugate allyl cuprate addition to a thus obtained 5-allyl dehydropiperidinone and ring-closing metathesis of the product gave a hydroquinolinone containing three stereogenic centers.