Copper-Promoted Cyanation of a Boron Cluster: Synthesis, X‑ray Structure, and Reactivity of 12-CN-closo-CHB11H10–

Microwave-assisted cross-coupling reactions of boron-iodinated derivatives of 1-carba-closo-dodecaborate­(1−) (1) with CuCN is shown to cyanate boron vertices of this anion. Clusters with one or two CN groups can be prepared: syntheses of 12-CN-CHB11H10– (3) and 7,12-(CN)2-CHB11H9– (6) gave yields of 80% and 81%, respectively. The [Et4N]+ salts of 3 and 6 were characterized by NMR, IR, and mass spectroscopies, and the crystal structure of [Et4N]3 was determined by single-crystal X-ray diffraction. Hydrolysis of 3 gave the carboxylic acid 12-COOH-CHB11H10– (7).