Preparation of Oxepanes, Oxepenes, and Oxocanes by Iodoetherification using Bis(sym-collidine)iodine(I) Hexafluorophosphate as Electrophile

Oxepanes have been obtained in good yields (40−95%) by iodoetherification of unsaturated alcohols using bis( sym -collidine)iodine(I) hexafluorophosphate (1 ) as electrophile, either by 7- exo -mode or 7- endo -mode cyclizations. 4-Oxepenes could also be formed from 4,6-heptadien-1-ols; the presence of a substituent on the carbon 6 appeared necessary, while for steric reasons the presence of a substituent on the carbon 7 was unfavorable. Oxocanes could be obtained in moderate yields (18−27%).