Nitrous acid elimination from 4-alkyl-5-formyl-4-nitrocyclohex-1-enes: synthesis of mono and bicyclic benzene and dihydrobenzene derivatives
作者:M.V Gil、E Román、J.A Serrano
DOI:10.1016/s0040-4039(01)00828-0
日期:2001.7
Elimination of nitrous acid from 4-alkyl-5-formyl-4-nitrocyclohex-1-enes, by treatment with silica gel or potassium carbonate, is described. Whereas in the former case the product consisted in a mixture of the starting material, 2-alkyl-4,5dimethylcyclohexa-1,4-diene-1-carbaldehyde and 2-alkyl-4,5-dimethylbenzaldehyde, reaction with potassium carbonate at 60 degreesC yielded exclusively aromatic compounds. Furthermore, when a ketone Function was present in the gamma -position of the ail;yl chain at C-4, the alkaline medium promoted an intramolecular. aldol condensation, bring obtained bicyclic products. PM3 calculations have been made to justify the result of the cyclization. (C) 2001 Elsevier Science Ltd. All rights reserved.