Reactivities of mixed organozinc and mixed organocopper reagents. Part 13 Kinetic study for phosphine-catalyzed acylation of alkylarylzincs and effect of residual group on the transfer rate of alkyl group

Pekel Ö.

Journal of Physical Organic Chemistry, vol.29, no.4, pp.190-195, 2016 (SCI-Expanded, Scopus) identifier identifier

  • Publication Type: Article / Article
  • Volume: 29 Issue: 4
  • Publication Date: 2016
  • Doi Number: 10.1002/poc.3517
  • Journal Name: Journal of Physical Organic Chemistry
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.190-195
  • Keywords: acylation of diorganozincs, kinetics of diorganozincs, mixed diorganozincs, phosphine catalyst, CONJUGATE MICHAEL-ADDITIONS, IMPROVED THERMAL-STABILITY, SELECTIVE LIGAND TRANSFER, ORGANIC GROUP-TRANSFER, CARBONYL-COMPOUNDS, GRIGNARD-REAGENTS, DIORGANOZINC COMPOUNDS, ASYMMETRIC-SYNTHESIS, ZINC REAGENTS, ATE COMPLEXES
  • Ankara University Affiliated: Yes

Abstract

Copyright © 2016 John Wiley & Sons, Ltd.Kinetics of reactions of di-n-butylzinc, n-Bu2Zn, and mixed n-butyl(substituted phenyl)zinc reagents and n-Bu(functional group (FG)-C6H4)Zn with benzoyl chloride in the presence of tri-n-butylphosphine have been investigated. Reaction rates of transferable n-butyl group have been determined in tetrahydrofuran at 0 °C to compare the transfer rate of n-butyl group in homo and mixed diorganozincs. Rate law is consistent with a third-order reaction, which is first order in diorganozinc, benzoyl chloride, and n-Bu3P, and a mechanism was proposed. The lower reaction rate of n-BuPhZn than that of n-Bu2Zn and negative reaction constant in Hammett plot are in accordance with the carbanionic charge of transferable n-butyl group in the acylation reaction. These findings support the hypothesis that the reaction rate of transferable group, RT, changes depending upon the residual group, RR, in RRRTZn reagents.