Neighboring Group participation by the tetrahydrofuran ring

Neighboring group participation in the solvolytic reactions of a series of ω‐(2‐tetx‐a‐hydrofuran)alkyl p ‐ bromobenzenesulfonate esters has been investigated. Anchimeric assistance to solvolysis is most pronounced in the case of 3‐(2‐tetrahydrofuran)propyl p ‐bromobenzenesulfonate where a 1‐oxabicyclo[3.3.0]octane cation can form. A “special salt effect” and an “induced common ion effect” were observed in the acetolysis of this ester. It appears that the tetrahydrofuran ring is about twice as effective as the methoxyl group in neighboring group participation.