Silica and alumina modified by Lewis acids as catalysts in Diels-Alder reactions of chiral acrylates

Article abstract of DOI:10.1016/S0957-4166(00)80163-9

Silica and alumina, modified by treatment with AlClEt₂ and TiCl₄, are tested as catalysts in the reactions of cyclopentadiene (1) with (-)-methyl acrylate (2a), (R)-O-acryloyl pantolactone (2b) and (S)-O-acryloyl lactate (2c). Silica-modified systems are the most efficient heterogeneous catalysts described to date for this kind of reaction, leading to selectivities similar to those obtained with aluminium homogeneous catalysts. Whereas silica· AlClEt₂ is better for the reaction of 2a and 2c, silica· TiCl₄ is more suitable for the reaction of 2b.