Pd(II)-catalyzed asymmetric Wacker-type cyclization for the preparation of 2-vinylchroman derivatives with biphenyl tetraoxazoline ligands

This article describes an efficient method for the preparation of chiral chroman derivatives by the Pd(II)-catalyzed asymmetric Wacker-type cyclization using a chelation-induced axially chiral tetraoxazoline ligand. Under the optimized conditions, up to 80% yield and up to 92% ee were obtained. This is the first example to utilize o-trisubstituted 3-butenylphenols as substrates in such transformation.