Using secondary alpha deuterium kinetic isotope effects to determine the stereochemistry of an E2 reaction; the stereochemistry of the E2 reaction of 1-chloro-2-phenylethane with potassium tert-butoxide in tert-butyl alcohol

Abstract

Isotopic labelling studies have shown that the E2 reaction of 1-chloro-2-phenylethane with potassium tert-butoxide in tert-butyl alcohol occurs via an anti-periplanar stereochemistry. This demonstrates that the different secondary alpha deuterium kinetic isotope effects found for the high and low base concentrations and in the presence of 18-crown-6 ether are because of changes in transition state structure that occur when the form of the reacting base changes rather than to a change in the stereochemistry of the reaction.Key words: E2 reaction, stereochemistry, secondary alpha deuterium kinetic isotope effects, transition state.

Stereochemistry of Transmetalation of Alkylboranes in Nickel-Catalyzed Alkyl–Alkyl Cross-Coupling Reactions

“…cis-1,2-Dideuteriostyene ( 1a ) was prepared by treating phenylacetylene with Cp 2 ZrDCl, followed by D 2 O, according to a procedure by Bercaw et al 1 H NMR spectroscopy indicated 93% deuterium incorporation, in accord with reported spectral data . The product was stored at −20 °C and used within 12 h of isolation.…”

The Effect of Inert Salts on the Structure of the Transition State in the SN2 Reaction between Thiophenoxide Ion and Butyl Chloride

“…It is worth noting that this type of catalysis to a chloride ion leaving group using hydrogen bonding to protic solvents in S N reactions has been suggested by Thornton and Gajewski. 20,21 Electophilic catalysis for the removal of a chloride ion leaving group by metal ions in E2 elimination reactions of alkyl chlorides was suggested by Smith et al 22 and by Zavada and co-workers. 23,24 If this type of catalysis occurred, it would stabilize the developing chloride ion making it a better leaving group.…”