A general method for the formation of the cyclic ethers 9, 10, 13, 14, 16, and 28 and the lactone 30 is described. The procedure employs benzenesulfenyl chloride prepared in situ in acetonitrile and N, N-diisopropylethylamine to generate a thiiranium (episulfonium) ion intermediate from which the cyclic products arise by internal nucleophilic displacement. In the special case of the norbornene alcohols 1 and 2 the oxetanes 5 and 6 are formed by ...
