Regioselective Reduction of Polyketones on Silica Gel Surface With Borane–trimethylamine Complex

Steroidal diones and trione, bicyclic diones (7 and 8) and a tricyclic dione were adsorbed on silica gel and reduced with BH3.NMe3. The carbonyl groups at C-3 of the steroids, at C-4 of 7 and at C-3 of 8 were reduced regioselectively. The FT-IR spectra of 5α- and 5β-androstane-3,17-dione adsorbed on silica gel were measured.