107. Silicon-Directed Regio- and Enantioselective Synthesis of α-Hydroxy-ketones

Article abstract of DOI:10.1002/hlca.19890720514

α-Silylated ketones (S)-2 (ee >/= 98percent), easily available through silylation or silylation/alkylation from ketones 1 using the (-)-(S)-1-amino-2-(methoxymethyl)pyrrolidine (SAMP)-/(+)-(R)-1-amino-2-(methoxymethyl)pyrrolidine (RAMP)-hydrazone method, are oxidized to give α-hydroxy-ketones (R)-5 of high enantiomeric purity (ee >/= 98percent) and in good overall yields (51-70percent).The key step of the procedure is the silicon-directed diastereoselective oxidation of the corresponding silyl enol ethers of (S)-2, with m-chloroperbenzoic acid or 3-phenyl-2-(phenylsulfonyl)oxaziridine, followed by flash chromatography and desilylation.