27948-74-9Relevant academic research and scientific papers
Potassium Borohydride Reductions of Ketones absorbed into Polymer Supports: Stereochemical Effects
Briggs, Josie C.,Hodge, Philip
, p. 310 - 311 (1988)
The proportions of 6α-alcohol obtained from aqueous potassium borohydride reductions of 3β-cholestan-6-one (1) absorbed into various polymers varied from 0 to 90percent depending on the polymer used and whether or not a phase transfer catalyst was added; some other ketones show similar streochemical effects, the greatest effects probably arising when the substrates are adsorbed to the inner surfaces of appropriate polymers.
Potassium borohydride reductions of immobilised ketosteroids
Briggs, Josie C.,Hodge, Philip,Zhengpu, Zhang
, p. 3943 - 3956 (2007/10/03)
Ketosteroids absorbed into various insoluble supports (powdered polyethylene, microporous 2% crosslinked polystyrene beads, macroporous highly crosslinked polystyrene beads, silica gel and alumina) call be reduced using aqueous potassium barohydride. The use of phase transfer catalysts generally raises yields. In the case of 6-ketosteriods the supported reactions often follow a stereochemical course significantly different from that of analogous reactions in solution. This is attributed to the adsorbtion of the steroid onto the inner surfaces of the supports. In these cases reduction of (he ketosteroid by alkoxyborohydrides is substantially suppressed and thus most of the reduction is brought about by BH4- itself, a relatively sterically undemanding reductant. The net result is that whilst reductions of 6-ketosteroids in solution by potassium borohydride typically gives the 69α- and 6β-alcohols in the ratio 15:85, with the supported steroid the ratios can be as high as 90:10.
