How to Protect ortho-Carborane from Decapitation—Practical Synthesis of 3,6-Dihalogen Derivatives 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I)

Abstract

The 3-halogen and 3,6-dihalogen derivatives of ortho-carborane 3-X-1,2-C2B10H11 and 3,6-X2-1,2-C2B10H10 (X = Cl, Br, I) were prepared by Cu-assisted halodeboronation of the corresponding pinacolborate derivatives 3-Bpin-1,2-C2B10H11 and 3,6-(Bpin)2-1,2-C2B10H10. It was shown that decapitation of 3-Cl-1,2-C2B10H11, similarly to the corresponding bromo and iodo derivatives, proceeds regioselectively with the retention of the B-Cl bond. Crystal structures of 3,6-Cl2-1,2-C2B10H10 and Cs [3-Cl-7,8-C2B9H11] were determined by single crystal X-ray diffraction.