The effect of residual group, RR on the reaction rate of transferable group, RT in the alkyl coupling of mixed cuprates, RRRTCuMgBr

Erdik E., Özkan D.

Reaction Kinetics, Mechanisms and Catalysis, vol.108, no.2, pp.293-304, 2013 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 108 Issue: 2
  • Publication Date: 2013
  • Doi Number: 10.1007/s11144-012-0531-4
  • Journal Name: Reaction Kinetics, Mechanisms and Catalysis
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Page Numbers: pp.293-304
  • Keywords: Kinetics of mixed cuprates, Mixed diorganocuprates, Residual group effect
  • Ankara University Affiliated: Yes

Abstract

For the investigation of the effect of residual group, RR on the transfer rate of transferable group, RT in mixed diorganocuprates, RRRTCuMgBr, a detailed direct kinetic study has been carried out and the reaction rates of the transferable group, n-Bu in mixed n-butyl(substituted phenyl)cuprates, n-Bu(FG-C6H4)CuMgBr in their reactions with n-pentyl bromide in THF at 25 C have been compared. A second order substitution reaction was found, which is first order with respect to both the cuprate and the alkyl electrophile. The correlation of the n-Bu group transfer rate to the Hammett substituent constants gave a positive reaction constant (ρ) and an evaluation depending on the reaction mechanism was given for the unexpected sign of the reaction constant of Hammett plot. This study provides a kinetic support for the commonly accepted hypothesis regarding the dependence of the RT group transfer ability on the strength of RR-Cu bond in reactions RRRTCuMgBr reagents. © 2012 Akadémiai Kiadó, Budapest, Hungary.