TRAJECTORY OF ELECTROPHILIC ATTACK ON TRISUBSTITUTED CYCLOPROPANES

In the reactions of 2-exo-methyl-encfo-tricyclo[3.2.1.02,4]octane (1) and 2-exo-methyl-endo-tricyclo-[3.2.1.02'4]oct-6-ene (12) with both mercuric ion and proton, the electrophile attacks the cyclopropane moiety at the corner with inversion. For the reactions with mercuric ion, the propensity toward inversion of configuration at the site of nucleophilic attack is accounted for in terms of the looseness of the transition state and the absence of substantial development of positive charge at the tertiary center. In contrast, the reactions with proton proceed with significant development of positive charge at the tertiary center and occur with reduced regiospecificity and with attack of nucleophile being less stereospecific. © 1990, American Chemical Society. All rights reserved.