Issue 36, 2020

Magnesium-mediated sp3 C–H activation in cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes: efficient synthesis of carborane-fused cyclopentanes

Abstract

This work reports an unprecedented cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes promoted by magnesium-mediated sp3 C–H activation. Treatment of 1-arylethynyl-2-alkyl-o-carboranes with MeMgBr gives a series of carborane-fused cyclopentanes in very good yields. Deuterium labelling and control experiments suggest that HMgBr, resulting in situ from the nucleophilic substitution of cage B–H bonds with Grignard reagent, initiates the reaction, in which magnesium-promoted intramolecular sp3 C–H activation serves as a key step. This work not only offers a new route for the synthesis of carborane-fused cyclopentanes, but also sheds some light on Mg-mediated C–H activation and functionalization.

Graphical abstract: Magnesium-mediated sp3 C–H activation in cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes: efficient synthesis of carborane-fused cyclopentanes

Supplementary files

Article information

Article type
Edge Article
Submitted
13 Aug 2020
Accepted
01 Sep 2020
First published
02 Sep 2020
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2020,11, 9925-9929

Magnesium-mediated sp3 C–H activation in cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes: efficient synthesis of carborane-fused cyclopentanes

J. Zhang, C. Tang and Z. Xie, Chem. Sci., 2020, 11, 9925 DOI: 10.1039/D0SC04465B

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