Conversion of 2‑Furylcarbinols with Alkyl or Aryl Azides to Highly Functionalized 1,2,3-Triazoles via Cascade Formal [3 + 2] Cycloaddition/Ring-Opening

A Lewis acid promoted cascade cycloaddition/ring-opening of 2-furylcarbinols with alkyl or aryl azides is described. The reaction features an initial formal [3 + 2] cycloaddition to form a trisubstitued triazole motif, followed by a ring opening of furan to generate the (E)-configuration of the enone. A wide range of highly functionalized triazoles is expediently and efficiently synthesized in a highly step-economical manner.