Abstract
N-Bromosuccinimide (1.1 eq) in the presence of potassium carbonate (2 eq) and a catalytic amount of dibenzoyl peroxide converts the allylic acetates and the allylic silyl ethers (O-TBDMS or O-SiEt3) of secondary allylic alcohols, derived from D-glucal 3a into corresponding dihydro γ-pyrones 2.