A procedure is reported for the conversion of tert-butyldimethylsilyl chloride and closo-1,2-C2B10H12 (1) to the corresponding silylcarborane derivative 2 in 99% yield. Compound 2 served as a valuable synthon to other monosubstituted carboranyl derivatives. Lithiation and reaction at the carborane 2-vertex with a variety of mono- and difunctional electrophiles under mild conditions formed the corresponding silylated products. Subsequent deprotection with tetrabutylammonium fluoride produced the corresponding monosubstituted carborane derivatives in high yield.