Issue 45, 2020

Identification of key functionalization species in the Cp*Ir(iii)-catalyzed-ortho halogenation of benzamides

Abstract

Cp*Ir(III) complexes have been shown to be effective for the halogenation of N,N-diisopropylbenzamides with N-halosuccinimide as a suitable halogen source. The optimized conditions for the iodination reaction consist of 0.5 mol% [Cp*IrCl2]2 in 1,2-dichloroethane at 60 °C for 1 h to form a variety of iodinated benzamides in high yields. Increasing the catalyst loading to 6 mol% and the time to 4 h enabled the bromination reaction of the same substrates. Reactivity was not observed for the chlorination of these substrates. A variety of functional groups on the para-position of the benzamide were well tolerated. Kinetic studies showed the reaction dependence is first order in iridium, positive order in benzamide, and zero order in N-iodosuccinimide. A KIE of 2.5 was obtained from an independent H/D kinetic isotope effect study. Computational studies (DFT-BP3PW91) indicate that a CMD mechanism is more likely than an oxidative addition pathway for the C–H bond activation step. The calculated functionalization step involves an Ir(V) species that is the result of oxidative addition of acetate hypoiodite that is generated in situ from N-iodosuccinimide and acetic acid.

Graphical abstract: Identification of key functionalization species in the Cp*Ir(iii)-catalyzed-ortho halogenation of benzamides

Supplementary files

Article information

Article type
Paper
Submitted
21 جمادى الثانية 1441
Accepted
20 شعبان 1441
First published
20 شعبان 1441

Dalton Trans., 2020,49, 16166-16174

Author version available

Identification of key functionalization species in the Cp*Ir(III)-catalyzed-ortho halogenation of benzamides

A. J. Guzmán Santiago, C. A. Brown, R. D. Sommer and E. A. Ison, Dalton Trans., 2020, 49, 16166 DOI: 10.1039/D0DT00565G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements