title: Elimination reactions of N-alkyl-N-chlorothenylamines promoted by MeONa-MeOH and Et(2)NH-MeCN. Effect of the beta-aryl group on the imine-forming transition state.
abstract: Elimination reactions of N-alkyl-N-chlorothenylamines 1-4 with MeONa-MeOH and Et(2)NH-MeCN have been studied kinetically. The elimination reactions are regiospecific, producing only the conjugated imines. The reactions are second order and exhibit substantial values of Hammett rho and k(H)/k(D), and an E2 mechanism is evident. The relative rates of elimination for Me/Et/i-Pr/t-Bu substituents are 1/0.5/0.2/0.02 with MeONa-MeOH and 1/0.4/0.2/0.06 with Et(2)NH-MeCN. The transition state structure changes toward more product-like as the base is changed from MeONa-MeOH to Et(2)NH-MeCN. Comparison with existing data reveals that the structure of the transition state is relatively insensitive to the beta-aryl group variation.
authors.affiliation: Department of Chemistry, Pukyong National University, Pusan 608-737, Korea. sypyun@pknu.ac.kr
authors.forename: Sang Yong
authors.initials: SY
authors.lastname: Pyun
authors.forename: Dong Choon
authors.initials: DC
authors.lastname: Lee
authors.forename: Yoon Je
authors.initials: YJ
authors.lastname: Seung
authors.forename: Bong Rae
authors.initials: BR
authors.lastname: Cho