biostudies-literatureZhang JResearch Grants Council, University Grants CommitteeChinese University of Hong Kong9925-9929https://www.ebi.ac.uk/biostudies/studies/S-EPMC8162123biostudies-literatureUnknown11(36)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.Chemical scienceMagnesium-mediated sp3 C-H activation in cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes: efficient synthesis of carborane-fused cyclopentanes.PMC816212314305918Zhang JXie ZTang CfalseMagnesium-mediated sp3 C-H activation in cascade cyclization of 1-arylethynyl-2-alkyl-o-carboranes: efficient synthesis of carborane-fused cyclopentanes.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.2020-01-01T00:00:00Z2020 Sep2025-04-04T08:18:21.5Z2022-02-10T13:57:56.494ZS-EPMC81621233409425310.1039/d0sc04465b