We report our discovery that tricyclohexyl phosphine is a privileged ligand that enables highly efficient Pd-catalyzed B-C(sp) bond formation on iodinated carborane precursors. We display the generality and utility of our reaction framework in the alkynylation of 9-I-m-carborane and demonstrate the first examples of monoalkynylation and symmetric dialkynylation on 9-I-o-carborane and 9,10-I2-m-carborane, respectively, under Sonogashira-type cross-coupling conditions across a broad range of diverse and complex alkyne-terminated coupling partners.
Hinkle et al. (Mon,) studied this question.