INTRAMOLECULAR FREE RADICAL CYCLISATIONS ONTO VINYL ETHERS. A METHOD FOR THE SYNTHESIS OF β-OXY-γ-BUTYROLACTONES

Article abstract of DOI:10.1016/S0040-4039(01)81427-1

Radical cyclisation of the vinyl ether bromides (2) and (7) in the presence of tri-n-butylstannane produces precursors to the β-oxy-γ-butyrolactones (6) and (9) in high yields (>80percent).By contrast, treatment of (2) and (7) with bis-(dimethylglyoximato)(pyridine)cobalt(I) chloride followed by oxidation of the intermediates (5) and (11) led to the corresponding unsaturated β-oxy-γ-butyrolactones (4) and (12) respectively.