Process for preparing optically active dihydropyrones

摘要

The invention relates to a process for preparing optically active 5-hydroxy-3-ketoesters of formula A1 or A2, or one of the tautomers thereof, the use thereof for preparing optically active dihydropyrones of formula B, and the use of the dihydropyrones of formula B thus prepared as starting compounds for preparing pharmaceutically active compounds, particularly Tipranavir.