Issue 46, 2018

Regioselectivity of aryl radical attack onto isocyanates and isothiocyanates

Abstract

The combination of multistage mass spectrometry experiments employing the distonic radical approach together with DFT calculations are used to examine addition of the N-methyl-pyridinium-4-yl radical cation (γ-NMP) to iso(thio)cyanates in the gas-phase. The type of products formed depend on the nature of the iso(thio)cyanate: (1) hydrogen atom abstraction occurs for alkyl isocyanates; (2) aryl isocyanates undergo radical-ipso substitution; (3) radical attack occurs at the C[double bond, length as m-dash]C bond of allyl isocyanate; (4) radical attack occurs at the C[double bond, length as m-dash]S bond of isothiocyanates to generate S adducts of γ-NMP and isonitriles. DFT calculations provide insight into the reactivity differences of these heterocumulenes towards the electrophilic C-centered γ-distonic radical cations. Translation of these gas phase results to the solution phase were hampered by dominating radical recombination reactions which appear to be favoured over the radical-iso(thio)cyanate reactions.

Graphical abstract: Regioselectivity of aryl radical attack onto isocyanates and isothiocyanates

Supplementary files

Article information

Article type
Paper
Submitted
07 Sep 2018
Accepted
05 Nov 2018
First published
14 Nov 2018

Org. Biomol. Chem., 2018,16, 9011-9020

Regioselectivity of aryl radical attack onto isocyanates and isothiocyanates

G. K. Weragoda, R. L. Pilkington, A. Polyzos and R. A. J. O'Hair, Org. Biomol. Chem., 2018, 16, 9011 DOI: 10.1039/C8OB02209G

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