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Transannulare Hydridverschiebung versus Cyclokondensation bei 5‐(2‐Biphenylyl)‐10,11‐dihydro‐5 H ‐dibenzo[ a , d ]cyclohepten‐5‐ol‐Derivaten
Author(s) -
Hellwinkel Dieter,
Becker Thomas
Publication year - 1989
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19891220832
Subject(s) - chemistry , cycloheptene , carbenium ion , nitromethane , deprotonation , hydride , medicinal chemistry , trifluoroacetic acid , acetic acid , isoquinoline , fluorene , stereochemistry , organic chemistry , ion , polymer , hydrogen
Transannular Hydride Shift versus Cyclocondensation in 5‐(2‐Biphenylyl)‐10,11‐dihydro‐5 H ‐dibenzo[ a , d ]cyclohepten‐5‐ol Derivatives The title compounds 1a – c , stable under thermal and basic conditions, undergo a solvent‐assisted concerted hydride shift/deprotonation reaction to 5‐(2‐biphenylyl)‐5 H ‐dibenzo[ a , d ]cycloheptene ( 4 ) in weak acids such as acetic acid, acetic anhydride, phenol, and nitromethane. In strong acids like formic acid or trifluoroacetic acid cyclization to 10,11‐dihydrospiro[5 H ‐dibenzo[ a , d ]cycloheptene‐5,9′‐fluorene] ( 3 ) occurs via the carbenium ion intermediate 5 .