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.

SUBMITTER: Zhang J 

PROVIDER: S-EPMC8162123 | biostudies-literature | 2020 Sep

REPOSITORIES: biostudies-literature