INFLUENCE OF POLAR GROUPS IN THERMAL AND LEWIS ACID PROMOTED ASYMMETRIC DIELS-ALDER ADDITIONS: LACTIC ACID DERIVATIVES AS PRACTICAL HIGHLY SELECTIVE AND CONFIGURATIONALLY DICHOTOMIC REAGENTS

Article abstract of DOI:10.1016/S0040-4039(01)80207-0

Diels-Alder reactions of the acrylate of (S)-ethyl lactate with cyclopentadiene proceed with diastereoface-selectivity of up to 85:15 (non catalyzed) and 93:7 (TiCl4-promoted).Depending on the Lewis acid, products of inverse configuration are obtained.In conjunction with facile product analysis by LC, effective means for suppression of the polymerization of diene, and virtually epimerization-free ester hydrolysis these findings constitute a method for large scale practical applications of the asymmetric Diels-Alder reaction.