Asymmetric transformation of narwedine-type compounds

摘要

A process for the asymmetric transformation of a racemic compound of formula (I) wherein R1 is H or a alkyl group having up to 20 carbon atoms, R2 is H, or an alkyl, aryl, alkaryl or aralkyl group having up to 20 carbon atoms, and X is H, a halogen atom, tert-butyl, or any other removable substituent, comprises reaction of racemic compound (I) with an enantiomerically-enriched acid HY*, wherein Y* is a chiral group, to form a diastereomeric salt of compound (I) having Y* as a counterion. The salt obtained can then be reduced to give enantiomerically-enriched galanthamine, or a derivative thereof.