Premium
Photocyclisation and Photocyclodehydrogenation of Stilbene and Related Compounds
Author(s) -
Bromberg A.,
Muszkat K. A.,
Fischer E.
Publication year - 1972
Publication title -
israel journal of chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.908
H-Index - 54
eISSN - 1869-5868
pISSN - 0021-2148
DOI - 10.1002/ijch.197200077
Subject(s) - chemistry , dehydrogenation , steric effects , phenanthrene , photochemistry , excited state , iodine , organic chemistry , catalysis , physics , nuclear physics
Abstract The reversible photocyclisation of cis ‐stilbene analogues to the corresponding dihydrophenanthrenes is not slowed down at high viscosities of the medium. Its attenuation at low temperatures is a true temperature effect. Methylation affects the photocylisation significantly only if it results in strong steric interactions in the cyclisation product. Photocyclodehydrogenation of stilbenes with oxygen to the corresponding phenanthrene analogues passes through the 4a, 4b‐dihydrophenanthrenes, and can be sensitized by various compounds at low concentrations. Photo‐oxidation with iodine probably involves dehydrogenation of ground‐state dihydrophenanthrene with atomic iodine. Electronically excited dihydrophenanthrenes may also be involved in the photo‐oxidation.