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TiO 2 ‐sensitised photo‐oxidation mechanism of indane and some of its hetero‐analogues in deaerated CH 3 CN
Author(s) -
Bettoni Marta,
Giacco Tiziana Del,
Rol Cesare,
Sebastiani Giovanni V.
Publication year - 2006
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1086
Subject(s) - chemistry , indane , indene , medicinal chemistry , photochemistry , substrate (aquarium) , alcohol , ketone , reaction mechanism , organic chemistry , catalysis , oceanography , geology
A mechanistic study, principally based on product analysis, relative to the TiO 2 ‐photosensitized oxidation of indane and some of its hetero‐analogues, in deaerated CH 3 CN and in the presence of Ag 2 SO 4 , was performed. In particular: (i) 1‐acetamidoindan (principal product), indene, 1‐indanol and 1‐indanone were obtained from indan; (ii) 5‐methoxyindan gave 6‐methoxyindene (principal product) and 5‐methoxy‐1‐indanone; (iii) 2,3‐dihydrobenzofuran, 2,3‐dihydroindole and 2,3‐dihydrobenzothiophene produced benzofuran, indole and benzothiophen (the last one accompanied by minor amounts of 2,3‐dihydrobenzothiophene‐1‐oxide), respectively. Considering the previous studies on photo‐oxidation of analogous substrates as benzylic derivatives (arenes, alcohols and ethers) and from reaction product profiles, an electron‐transfer mechanism (from the substrate to the photogenerated hole) is suggested, where the radical cation intermediate should deprotonate to a benzylic radical. The carbocation obtained from the oxidation of this radical should competitively evolve to alkene, alcohol and acetamide. H 2 18 O labelling photo‐oxidation experiments suggest that the ketone, when present, should derive from the substrate, through the alcohol as intermediate. Copyright © 2006 John Wiley & Sons, Ltd.