Treatment of the E-α, β-unsaturated selenyl esters 1 and 3a with Bu3SnH-AIBN produces the corresponding cyclohexenones 2 and 7 8 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.