A study of the stereochemistry of the dealkoxycarbonylation of some sulfur-substituted cyclopropanes.
CONGIU, CENZO;ONNIS, VALENTINA
1997-01-01
Abstract
2-sulfenyl- and 2-sulfonyl-phenyl groups can affect the stereochemistry of the products in the reaction of some ester-stabilized cyclopropyl carbanions. As these substituents are not particularly effective chelating groups, the possibility of the intervention of a ct anomeric effect between the sulfur atom and the more extended orbital lobe of the cyclopropyl carbanion is considered. Evidences of the intermediacy of a pyramidal ester enolate are presented. The dimethyl 3-isopropyl-2-phenylsulfonyl-1,1-cyclopropane dicarboxylate 12 undergoes dealkoxycarbonylation, probably through a ring-opening ring-closure process, to give the corresponding monoester 15 with complete control of the relative stereochemistry of the three substituents.Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.