The Paternò-Büchi Reaction of 2-Furylmethanols

Abstract

The Paternò-Büchi reaction between 2-furylmethanol derivatives and aromatic carbonyl compounds shows good regioselectivity and high stereoselectivity. The regio- and stereoselectivity of the reaction can be explained by assuming a role of both the substituent on the 2-furylmethanol derivative and the hydroxy group in order to favor the approach of the carbonyl group towards a prochiral face of the furan. Electrochemical and kinetic properties of 2-furylmethanols are in agreement with an electron-transfer mechanism. The stereoselectivity of the reaction was confirmed using chiral 2-furylmethanols: These substrates gave the corresponding Paternò-Büchi adducts with high enantiomeric excess.