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Photochemical Reactions of 1,3,3‐Trimethylbicyclo[2.2.2]octa‐5,7‐dien‐2‐ones
Author(s) -
Chang ShiYi,
Huang ShihLin,
Villarante Nelson R.,
Liao ChunChen
Publication year - 2006
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.200600451
Subject(s) - chemistry , acetophenone , acetone , acetonitrile , photochemistry , solvent , bicyclic molecule , methanol , benzene , ketone , solvent effects , medicinal chemistry , mechanistic organic photochemistry , organic chemistry , catalysis
The photochemistry of 1,3,3‐trimethylbicyclo[2.2.2]octa‐5,7‐dien‐2‐ones 1a – f containing multiple chromophoric moieties under various conditions is described. Upon direct irradiation, dienones 1a – f in benzene, acetonitrile, and methanol were found to aromatize through photoelimination of dimethylketene, which was trapped with 3‐phenylprop‐2‐en‐1‐ol ( 12 ). Triplet sensitization of dienone 1a in acetone and in acetone/acetophenone mixed solvents afforded aromatic compound 2a , whilst bicyclic systems 1b – c were found to be unreactive on sensitization. In the cases of dienones 1d – f in acetone, aromatic compounds 2d – f and di‐π‐methane (DPM) photoproducts 3d – f and 4f were observed, but in the acetone/acetophenone mixed solvent system only DPM photoproducts were detected. Plausible mechanisms for these photochemical reactions are described. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)