Photocyclisation of enamides. Part 14. Substituent effects in the photocyclisation of N-α,β-unsaturated acylanilides

Abstract

Irradiation of N-α,β-unsaturated acylanilides [(1a–d and 1i) and (2a–f and 2h)] having various substituents on the benzene ring yielded a mixture of cis- and trans-octahydrophenanthridones (3a–f) and dihydroquinolones (5a, e, and f). The N-alkylanilides [(1e–h) and (2b–d)] having an ortho-electron-attracting group, such as CO₂Me, Ac, CN, or CONH₂, brought about [1,5] migration of the group to afford the trans-lactams (4a–d) and dihydroquinolones (5b–d), while anilides [(1j), (2g), and (8a–c)] having an ortho-carboxy-group afforded the decarboxylactams [(3a), (5a), (9a–c), and (10b and c)].