- The Synthesis of 4-Methylcyclohexa-2,5-dienones from Phenols
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4-Alkyl phenols have been converted by a known sequence into 2-aryloxyisobutyric acids and thence, by bromination at the 4-position of the aromatic ring with concomitant intramolecular lactone formation, into masked 4-alkyl-4-bromocyclohexa-2,5-dienones.Reaction with lithium dimethylcuprate, as a model for other lithium dialkylcuprates, replaces the bromine by a methyl group.Hydrolytic demasking gives 4-alkyl-4-methylcyclohexa-2,5-dienones.The method should allow the general synthesis of 4-alkylated cyclohexa-2,5-dienones from phenols via a nucleophilic alkylation step.This contrasts with an existing route which uses electrophilic alkylation of phenols or phenoxide ions by a restricted range of reactive alkylating agents.
- Islam, M. Majharul,Waring, Anthony J.
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p. 768 - 783
(2007/10/02)
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