Synthesis of Dicarba-closo-dodecaborane-1-carboxamides

Amide bond formation is one of the most important chemical reactions. In peptide and organic chemistry, the application of amide coupling reagents is a routine strategy, but surprisingly not in carborane chemistry. Thus, we now report a fast, safe, and robust protocol to couple amines to m- and p-dicarba-closo-dodecaborane-1-carboxylic acids. The procedure comprises the activation of carboxylic acid with the coupling reagent (1-cyano-2-ethoxy-2-oxoethylidenaminooxy)(dimethylamino)morpholinocarbenium hexafluorophosphate, extraction of the product using the hydrophobic nature of the cluster, and a straightforward chromatographic purification. The protocol allows access to a variety of carborane–organic hybrid molecules suitable for application in multiple areas.