Model studies of the overall 5-endo-trig iodocyclization of homoallylic alcohols

Overall 5-endo-trig iodocyclizations of homoallylic alcohols, with a range of substitution patterns, leading to β-iodotetrahydrofurans are usually highly efficient and stereoselective when carried out in anhydrous acetonitrile in the presence of sodium hydrogen carbonate. Such cyclizations, which are not exceptions to Baldwin's rules as they are electrophile-driven, appear to proceed via a well-ordered chair-like transition state. The iodine can be replaced by hydroxy, acetoxy and azide groups