G. Bellucci, F. Marioni, A. Marsili
1972
Citations
0
Influential Citations
15
Citations
Journal
Tetrahedron
Abstract
Abstract Bromination of 3-cyclohexene-1-carboxylic acid ( 1 ) gives mixtures of the trans -dibromo-derivatives 3 and 4 and cis -3-hydroxy- trans -bromocyclohexane-1-carboxylic acid lactone ( 5 ). Lactone 5 is obtained by brominating 1 in the presence of triethylamine, showing that halogen preferentially attacks the double bond anti with respect to the carboxyl group. Epoxydation of the methyl ester of 1 also takes place prevalently anti to the methoxycarbonyl group. Ring opening of methyl cis -3,4-epoxycyclohexane-1-carboxylate ( 7 ) with hydrogen bromide gives methyl trans -3-bromo- cis -4-hydroxy- ( 13 ) and cis -3-hydroxy- trans -bromocyclohexane-1-carboxylate ( 6 ). Similar opening of methyl trans -3,4-epoxycyclohexane-1-carboxylate ( 11 ) affords methyl trans -3-hydroxy- cis -4-bromocyclohexane-1-carboxylate ( 14 ). The steric course of these reactions is ascribed to the effect of the electron-withdrawing substituent.