The 2-methyl ketone (2a, b), which are derived from the ketones (1a, b), afford the cis-imines (7a, b) and trans-imines (8a, b) by the Leuckart and Bischler-Napieralski reactions. Their methiodies (9a, b and 10b) are converted into the cis-lactams (15a, b) and trans-lactam (17b) via oxidation of the pseudo cyanides (14a, b and 16b). Bromination and successive dehydrobromination of 2a give the enone (20) which affords the cis-imine (23) and trans-imine (24) by the same procedure as above. The cis-methiodide (25) of 23 is reduced to give the cis-amine (26). The cis-lactams (15a, b) and cis-amine (26) can be connected with the synthetic methods of corynoline analogues, which were already known.
