Synthesis of C-Methoxy- and C,C’-Dimethoxy-ortho-carboranes

Abstract

a simple way to the synthesis of mono- and disubstituted methoxy derivatives of closo- and nido-carboranes is suggested. C-methoxy- and C-methoxy-C’-methyl-ortho-carboranes were prepared by the treatment of C-hydroxy-ortho-carborane with iodomethane in the presence of sodium hydride in 1,2-dimethoxyethane. C,C’-dimethoxy-ortho-carborane was synthesized from C,C’-dihydroxy-ortho-carborane in the similar way. All methoxy derivatives of closo-carborane were converted to the corresponding nido-carboranes by the deboronation reaction with cesium fluoride. The tetrasubstituted cobalt bis(dicarbollide) complex K[1,1′(2′)-(MeO)2–2,2′(1′)-Me2–3,3′-Co(1,2-C2B9H10)2] was prepared by the reaction of CoCl2 and C-methoxy-C’-methyl-nido-carborane in the presence of t-BuOK in 1,2-dimethoxyethane.