ELIMINATIONS FORMING CARBON-HETEROATOM MULTIPLE BONDS - BASE-PROMOTED DEHYDROCHLORINATION OF N-CHLOROBENZYLMETHYLAMINES

Reactions of N-chlorobenzylmethylamines, 1, with MeONa-MeOH and t-BuOK-t-BuOH have been studied kinetically. The eliminations are quantitative and regiospecific, producing only benzylidenemethylamines. The reactions are first order in base and first order in chloramine and an E2 mechanism is evident. Reactions of I with MeONa-MeOH and t-BuOK-t-BuOH give Hammett p values of + 1.52 and +1.68, respectively. From eliminations of PhCD2N(Cl)CH3 and its un-deuterated analogue induced by MeONa-MeOH and t-BuOK-t-BuOH, kH/kD values of 5.1-6.5 were calculated. For eliminations from N-halobenzylmethylamines, kBr/kCl = 11.9 and 10.8 were observed with MeONa-MeOH and t-BuOK-t-BuOH, respectively. Comparison of these results with those for eliminations from 2-halo-l-phenylpropanes provides insight into closely related imine- and alkene-forming eliminations. Copyright © 1979, American Chemical Society. All rights reserved.