Pd(II)/PIDA-Enabled Migratory Triple Functionalization of Terminal Alkenes via a 1,2-C/Pd(IV) Dyotropic Rearrangement.

Abstract

We report a Pd(II)-catalyzed migratory triple functionalization of terminal alkenes. The reaction of homoallylic amides with phenyliodine(III) diacetate (PIDA) under Pd(II) catalysis delivers 6-acetoxylated 5,6-dihydro-4H-1,3-oxazines through the formation of one C─C and two C─O bonds. Mechanistic studies suggest a sequence involving oxypalladation, oxidation of Pd(II) to Pd(IV), a 1,2-alkyl(aryl)/Pd(IV) dyotropic rearrangement (DR), and subsequent acetoxylation. While Pd(II)/Pd(IV) catalysis with PIDA as the oxidant has enabled numerous powerful transformations, the DR reported here is unprecedented.