Either diastereofacial differentiation in the reaction of chiral thiomethylketones with appropriate organometallics

Article abstract of DOI:10.1016/S0040-4039(00)97877-8

Introduction of sulfur atom instead of oxygen into α-position to ketone was found to be crucial for efficient diastereofacial differentiation; i.e., either diastereomer of tertiary alcohol could be obtained by the reaction of organometallics to chiral thiomethylketones derived from (S)-2-mercapto-2-phenylethanol and α-halo ketones. For example, MeLi attacked from si-face, while Me₂Zn preferred re-facial attack. In addition, both enantiomers of 1,2-O-isopropylidene-2-methyl-1,2,5-pentanetriol, a key intermediate for the synthesis of frontalin, were successfully synthesized utilizing the present method.