Boron Lewis Acid-Assisted Chiral Phosphoric Acid Catalystsfor Enantioselective Carbonyl-Ene Cyclization/Acetalization

摘要

Carbonyl-ene reaction is one of the most important carbon-carbon bond formingreactions to synthesize homoallylic alcohols with great atom economy.In particular,thetwo adjacent carbon atoms generated from this reaction can be sterically controlled by thechiral catalysis strategies.At the last CSJ annual meeting,we reported theenantioselective carbonyl-ene cyclization reaction of alkenyl aldehydes with the use ofchiral supramolecular phosphoric acid catalysts,1 which were prepared in situ from stericallyhindered chiral phosphoric acids and tris(pentafluorophenyl)borane.