SYNTHESIS AND STRUCTURAL ASSIGNMENT OF DIASTEREOMERICALLY PURE N-SUBSTITUTED 4-ALKYLPYRROLIDIN-2-ONES, INTERMEDIATES FOR THE PREPARATION OF3-ALKYLPYRROLIDINES IN BOTH ENANTIOMERICALLY PURE FORMS

By radical cyclisation of N-[(S)-1-phenylethyl]-N-allyliodoacetamides (6a-d), 4-substituted pyrrolidin-2-ones (7a-d) and (8a-d) were prepare d as diastereomeric equimolar mixtures which were separated by column chromatography. The preferred conformation of 7a-d and 8a-d was determ ined by molecular mechanics methods and the configuration of the newly introduced stereogenic center was assigned by H-1 nmr data and furthe r confirmed by NOE experiments. Compounds (7a-d) and (8a-d) can be con verted into 3-alkylpyrrolidines in both enantiomerically pure forms fo llowing procedures reported in the literature.