α-ketene alkyl and α,β-unsaturated acyl radical intermediates in ring constructions

Abstract

Treatment of the E-α,β-unsaturated selenyl esters 1 and 3a with Bu3SnH-AIBN produces the corresponding cyclohexenones 2 and 78 respectively via presumed α-ketene alkyl radical intermediates. In a similar manner the cyclopropyl ester 9 leads to a mixture of 12 and 13, and the 2,7-diene selenyl ester 15 undergoes a novel bi-cyclisation producing the diquinane 17 in 76% yield.