INTERMOLECULAR AND INTRAMOLECULAR SELECTIVITY IN THE CYCLIZATION OF N-CINNAMOYL-1-NAPHTHAMIDES IN SOLID-STATE PHOTOCHEMISTRY AND PERI SELECTIVITY IN THEIR PHOTOCYCLIZATION IN SOLUTION

The photocyclisation of N-cinnamoyl-1-naphthamides 1a-f was examined i n the solid state and in solution. Three types of cyclisation, intramo lecular 2 pi + 2 pi and 4 pi + 2 pi, and intermolecular 2 pi + 2 pi cy clisations were observed in the solid state. The ratios of these produ cts were largely dependent on the substituents at the para-position of the cinnamoyl moiety. Single-crystal X-ray crystallographic analysis of Ib showed that the intermolecular distance between the two double b onds was 4.34 Angstrom. Amides with bulky substituents preferred intra molecular 2 pi + 2 pi cyclisation. In contrast to the solid-state phot ochemistry, only intramolecular cyclisation was observed in solution. The ratios of 2 pi + 2 pi and 4 pi + 2 pi cyclisation products were ir radiation time dependent. It was found that the 2 pi + 2 pi cyclorever sion and rearrangement from the 2 pi + 2 pi product to the endo 4 pi 2 pi isomer were the cause of this dependency.