On hydrolysis, the bicyclohexanes 1a,b give the cyclobutanes 2a,b
and/or the cyclobutenes 3a,b. On bromination they lead to the
bromocyclobutanes 5a,b and the dibromocyclobutane 6a or the
bromocyclobutene 7b, respectively. The ease of the electrophilic
ring-opening of compounds 1a,b can be explained by assuming that the
presence of the methoxycarbonyl and gem-dimethoxy groups at C-1
and C-2 favours the formation of well-stabilized ionic intermediates or
polar transition states. However, the brominations may involve radical
pathways, even to a minor extent, and these would lead to the same
products.
Graziano M. Liliana, Iesce M. Rosaria, Cermola Flavio, Ialongo Guiseppina+, J. Chem. Res. Synop, (1995) N 5, S 176-177
作者:Graziano M. Liliana, Iesce M. Rosaria, Cermola Flavio, Ialongo Guiseppina+
DOI:——
日期:——
Reaction of small-size cycloalkane rings with RuO4. Oxidative scission of ethyl 2,2-dimethoxycyclopropane-1-carboxylates and methyl 2,2,6,6-tetramethoxybicyclo[2.2.0]hexane-1-carboxylates
oxidative ringopening by regioselective scission of the electron-rich C1C2 bond for 1a-d, and both C1C2 and C1C6 bonds for 5a and 5b. Methyl ethyl oxobutanedioates 2a-d were obtained in the first case while the 3-substituted ethyl methyl 2-oxopentanedioates 6a and 6b in the second one. In the same reaction conditions, cyclopropanessubstituted with electron withdrawing groups, namely cyclopropyl methyl