Palladium(II)-catalyzed asymmetric coupling of allylic alcohols and vinyl ethers: insight into the palladium and copper bimetallic catalyst

Abstract

The use of PdX(2), CuX(2) (X = OAc, OCOCF(3), or Cl), and catechol together with (S,S)-4,4'-bisbenzyl-2,2'-bioxazoline under O(2) induces the asymmetric coupling of cinnamyl alcohols and vinyl ethers to give (R)-(+)-2-alkoxy-4-benzylidenetetrahydrofurans in 40-53% ee (79% yield). The present study provides implications for the so-called Wacker catalyst of PdX(2) and CuX(2), in terms of that the anionic ligands (X) of Pd and Cu interchange between two metals.