Solvent-free asymmetric vinylogous aldol reaction of Chan's diene with aromatic aldehydes catalyzed by hydrogen bonding

Chan's diene proved to react with aromatic aldehydes under organocatalytic conditions in presence of a chiral naphthyl-TADDOL derivative to give vinylogous aldols (up to 65% ee) with complete gamma-selectivity. A further process of hetero-Diels-Alder cycloaddition, leading to chiral pyran-4-one derivatives (up to 60% ee), was favoured by electron-withdrawing substituents on the aromatic ring. (C) 2009 Elsevier Ltd. All rights reserved.