Yukiko Tada

Photocyclisation of enamides. Part 23. Reductive photocyclisation of enamides

Irradiation of the enamides (1), (9), and (13) in the presence of sodium borohydride led to reductive photocyclisation to afford two types of hydrogenated lactams, the lactams with a conjugated diene moiety (4a–c), (5), (10a and b), and (11) and the lactams with an unconjugated diene moiety (6a–c), (12a and b), and (14) respectively, whose ratios were dependent on the solvent used. Deuterium-incorporation experiments provided important information on the mechanism of this reductive photocyclisation.

Photocyclisation of enamides. Part 21. Synthesis of benzo[a]quinolizines related to the alkaloids emetine and flavopereirine

Acylation of 3,4-dihydro-1-methylisoquinoline with substituted acryloyl chlorides followed by irradiation of the resulting enamides provides a useful synthetic route to the benzo[a]quinolizines (4), (8a–d), and (9a) and (9b), and has been applied to a new total synthesis of flavopereirine (14).