Resolution and absolute configuration of 1,2,3,5,6,10bβ‐hexahydro‐6α‐phenylpyrrolo[2,1‐α]isoquinoline (McN‐4612‐Z). A problem of determination of the enantiomeric purity for a tertiary amine

Details for the resolution of 1,2,3,5,6,10bβ‐hexahydro‐6α‐phenylpyrrolo[2,1‐α]isoquinoline(1), a potent antidepressant‐like compound, into its enantiomers with di‐p‐toluoyltartaric acid (2)are reported. Enantio‐merically‐enrichedR‐(+)‐2‐phenylpyrrolidine was transformed into enantiomerically‐enriched1to determine enantiomeric purity and absolute stereochemistry for the resolved amines1. Thus, we ascertain that samples of (+)‐ and (—)‐1with an enantiomeric purity of ≥99% were prepared, and that bioactive (+)‐1possesses the 6S,10bRabsolute configuration. The enantiomeric purity of ≥99% was confirmed by 360‐MHz1H nmr examination of 1:1 diastereomeric salts formed from1or (—)‐1and (+)‐Mosher's acid (MTPA). The maximal optical rotation reported (ref 8) for (+)‐3(100% o.p.) was shown to correspond to 100% e.e.