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‐enriched R ‐(+)‐2‐phenylpyrrolidine was transformed into enantiomerically‐enriched 1 to determine enantiomeric purity and absolute stereochemistry for the resolved amines 1 . Thus, we ascertain that samples of (+)‐ and (—)‐ 1 with an enantiomeric purity of ≥99% were prepared, and that bioactive (+)‐ 1 possesses the 6 S ,10b R absolute configuration. The enantiomeric purity of ≥99% was confirmed by 360‐MHz 1 H nmr examination of 1:1 diastereomeric salts formed from 1 or (—)‐ 1 and (+)‐Mosher's acid (MTPA). The maximal optical rotation reported (ref 8) for (+)‐ 3 (100% o.p.) was shown to correspond to 100% e.e.