Asymmetric Allylic Etherification of Vinylethylene Carbonates with Diols via Pd/B Cooperative Catalysis: A Route to Chiral Hemi-Crown Ethers.

Pd-catalyzed regio- and enantioselective allylic etherification of vinylethylene carbonates (VECs) with diols has been developed. By using cooperative catalysts of the chiral palladium complex and triethylborane in mild conditions, the process gave monoetherified and bisetherified polyglycol derivatives with tetrasubstituted stereocenters in high yields with complete regioselectivities and high levels of enantio- and diastereoselectivities.