A kinetic study on the pairwise competition reaction of alpha-diazo esters with rhodium(II) catalysts: implication for the mechanism of Rh(II)-carbene transfer

Z Qu; W Shi; J Wang

doi:10.1021/jo0107352

A kinetic study on the pairwise competition reaction of alpha-diazo esters with rhodium(II) catalysts: implication for the mechanism of Rh(II)-carbene transfer

J Org Chem. 2001 Nov 30;66(24):8139-44. doi: 10.1021/jo0107352.

Authors

Z Qu¹, W Shi, J Wang

Affiliation

¹ Key Laboratory of Bioorganic Chemistry and Molecular Engineering of Ministry of Education, Department of Chemical Biology, College of Chemistry, Peking University, Beijing 100871, China.

PMID: 11722217
DOI: 10.1021/jo0107352

Abstract

The relative rate constants for the Rh(II)-mediated diazo decomposition of a series of para- or meta-substituted diazophenylacetates were measured through intermolecular competition. The kinetic data were further subjected to Hammett correlation analysis and were found to have better linear correlation with sigma(+). Reaction constants for four Rh(II) catalysts have been obtained, Rh(2)(OAc)(4) (rho = -1.29 with sigma(+), r = -0.99), Rh(2)(Ooct)(4) (rho = -1.31 with sigma(+), r = -0.99), Rh(2)(acam)(4) (rho = -1.18 with sigma(+), r = -0.99), Rh(2)(O(2)CCF(3))(4) (rho = -1.46 with sigma(+), r = -0.99). The mechanistic implications of these data are discussed.