Stereoselective intramolecular cyclization of allyl and homoallyl benzamide via π-allylpalladium complex catalyzed by Pd(0)

Article abstract of DOI:10.1021/jo991065r

The transformation of acyclic allylic benzamides 4 and homoallylic benzamides 12 to vinyl oxazolines 3 is achieved in the presence of base by the catalysis and Pd(0) in high yield and with high diastereoselectivity. Especially, in the case of homoallylic benzamides 12, trans-oxazolines 3 are formed exclusively or predominantly over cis-oxazolines 8, irrespective of the composition of their stereoisomers. The reaction is believed to proceed via the same π-allylpalladium complex that arises from either primary or secondary allylic acetates. We applied this method to the syntheses of β- amino-α-hydroxy acids 1 and γ-amino-β-hydroxy acids 2, conveniently protected as oxazoline.