Competitive kinetic study of the amination of organomagnesium and -zinc reagents with acetoneO-sulfonyloxime

Abstract

Kinetic studies are reported for the electrophilic amination of substituted phenylmagnesium bromides and CuCN-catalyzed phenylzinc chlorides with acetone O-(2,4,6-trimethylphenylsulfonyl)oxime in tetrahydrofuran at reflux temperature and at room temperature respectively. Substituent effects were determined by competition experiments. Rate data are analyzed via Hammett relationships to support the proposed mechanisms for the substitution of these organometallics with an electrophilic amino transfer reagent.

Sulfonyl transfer mechanism in C–S coupling of phenylmagnesium bromide with phenyl arenesulfonates

“…For the correlation, the point for the 4-CH 3 O substituent lying significantly of the linear plot was not used. However, a number of deviations have been already reported with 4-CH 3 O containing reactants in the Hammett plots for Grignard reactions [36][37][38]. The high q value indicates that the reactivity of the arenesulfonates is significantly increased by the electron withdrawing effect of the substituents, as expected.…”

Kinetics and mechanism of the C-S coupling reactions of aryl Grignard reagents with aryl arenesulfonates

“…For the correlation, we did not use the point for the 4--CH 3 O substituent lying significantly off the linear plot. In fact, deviations have been already reported with 4-CH 3 O and also with 4-Br and 3-Br containing phenylmagnesium reagents in the Hammett plots for their reactions [43][44][45].…”

Reactivity of mixed organozinc and mixed organocopper reagents. Part 4: a kinetic study of group transfer selectivity in CC coupling of mixed diorganocuprates

“…We have already used a similar equation successfully in the competitive amination kinetics of phenyl and substituted phenyl carbanions derived from Grignard reagents,51, 52 stoichiometric magnesium–copper reagents51 and catalytic zinc‐copper reagents 52. We have also used the competitive rate date in the application of Hammett methodology for the amination reactions 51, 52…”