Enantioselective Diels–Alder Reaction of 1,2-Dihydropyridines with Aldehydes Using β‑Amino Alcohol Organocatalyst

The enantioselective Diels–Alder reaction of 1,2-dihydropyridines with aldehydes using an easily prepared optically active β-amino alcohol catalyst was found to provide optically active isoquinuclidines, an efficient synthetic intermediate of pharmaceutically important compounds such as oseltamivir phosphate, with a satisfactory chemical yield and enantioselectivity (up to 96%, up to 98% ee). In addition, the obtained highly optically pure isoquinuclidine was easily converted to an optically active piperidine having four successive carbon centers.