
%0 Journal Article
%A Schiesser, Carl H. 
%A Skidmore, Melissa A. 
%A White, Jonathan M. 
%T Stannanes from Cholic Acid as Enantioselective Free-Radical Reducing Agents
%J Australian Journal of Chemistry
%D 2001/08/08
%V 54
%N 3
%P 199-204
%K 
%R https://doi.org/10.1071/CH01045
%U https://www.publish.csiro.au/paper/CH01045 
%X 7&#945;-(Dimethylstannyl)-24-nor-5&#946;-cholane (12) and 3&#946;-(dimethylstannyl)-24-nor-5&#946;-cholane (11) have been prepared from cholic and lithocholic acid, respectively, as free-radical reducing agents. Limited enantioselectivity-testing data indicate that these compounds show promise as enantioselective free-radical reducing agents. For example, reaction of ethyl (rac)-2-bromo-2-cyclopentyl-2-phenylacetate with one equivalent of either (11) or (12) in the presence of one equivalent of (S,S)-(&#8211;)-N,N&#8217;-bis(3,5-di-tert-butylsalycidene)-1,2-cyclohexanediaminomanganese(III) chloride (7) in toluene at &#8211;78&#x02DA;C provides ethyl (S)-2-cyclopentyl-2-phenylacetate, obtained with 62 and 90% ee, respectively. 
