Bi(OTf)3‐catalyzed Intermolecular Cyclization of Phenols with Allylic Alcohols.

The intermolecular cyclization of phenols with a small excess of allylic alcohols in the presence of a Bi(OTf)3 catalyst under air without any additives afforded the corresponding O‐containing heterocyclic compounds. Bi(OTf)3‐catalyzed intermolecular cyclization of phenols with 3‐methylbut‐2‐en‐1‐ol gave the corresponding O‐containing 6‐membered ring; chroman derivatives (16 varieties). The catalytic intermolecular cyclization of phenols with 2‐methylprop‐2‐en‐1‐ol led to the corresponding O‐containing 5‐membered ring; naphtho‐ or benzofurans (5 varieties). The intermolecular catalytic cyclization of 2,3,5,6‐trimethylbenzene‐1,4‐diol with a small excess of phytols produced vitamin E (DL‐α‐tocopherol) in excellent yields under mild reaction conditions. [ABSTRACT FROM AUTHOR]