Improved Synthesis of Icosahedral Carboranes Containing Exohedral B–c and C–c Bonds

26 October 2018, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


We report improved methods utilizing orthogonal chemistry to achieve efficient substitution at electron-rich B-vertices and electron-poor C-vertices of carborane. Functionalization of B-vertices with alkyl and (hetero)aryl groups using corresponding Grignard reagents has been improved by the use of a Pd-based precatalyst featuring an electron-rich biaryl phosphine ligand. Using the developed catalytic conditions lead to cross-coupling transformations achieved within several hours. Importantly, this method is applicable towards alkyl-based Grignard reagents containing β-hydrogens. Additionally, transition metal-free substitution of (hetero)aryl substrates on C-vertices was developed under SNAr conditions. The selective substitution of carboranes afforded by these methods holds potential for the rational synthesis of heterofunctionalized boron clusters with substituents on both boron and carbon-based vertices.


boron clusters
nucleophilic aromatic substitution

Supplementary materials

SI Procedures and Data


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