GLYCOSYLCARBORANE DERIVATIVES AND THE DETERMINATION OF THE ABSOLUTE-CONFIGURATION OF A DIASTEREOMERIC TRIOL FROM X-RAY-DIFFRACTION

Lithiated 1,2-dicarba-closo-dodecaboranes (carboranes)1 react with aldehydic sugars to give the corresponding hydroxyalkylated carboranes in good yields. In tetrahydrofuran solutions, high diastereoselectivity is observed. A single-crystal X-ray structure of a typical reaction product (le) confirmed that the erythro isomer was the major diastereomer formed. Epimeric inversion was accomplished by a simple oxidation–reduction sequence, which can introduce a tritium label into the glycosylcarborane. A representative l-(hydroxyalkyl)-2-phenyl-1,2-dicarba-closo-dodecaborane was converted to a m-diazonium ion and coupled to β-naphthol. © 1990, American Chemical Society. All rights reserved.