Tetracyclic triterpenes. XII. Reduction of 7-carbonyl group in 4,4,14 alpha-trimethyl-5 alpha-cholestane with unnatural 9 beta-configuration.
The carbonyl group in 3 beta-acetoxy-9 beta, 11 beta-epoxy-5 alpha-lanostan-7-one (1) was found resistant to reductions with conventional mild reducing agents. Reduction with LiAlH4 proceeded with unusual stereochemistry reflecting the steric crowding of the 7-carbonyl group in the folded conformation of the substrate possessing the unnatural 9 beta-configuration.
Paryzek
Z
Z
Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland.
D000535:Aluminum; D017607:Aluminum Compounds; D055598:Chemical Phenomena; D002621:Chemistry; D002776:Cholestanes; D008094:Lithium; D018020:Lithium Compounds; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D014315:Triterpenes / Q000138:chemical synthesis*
D017607:Aluminum Compounds; D002776:Cholestanes; D018020:Lithium Compounds; D014315:Triterpenes; C060443:4,4,14-trimethylcholestane; C042073:lithium aluminum hydride; D008094:Lithium; D000535:Aluminum