α-Amino Acids andN-Protected α-Amino Aldehydes by Stereoselective Additions of a Chiral Vinyllithium Reagent to Sulfonylimines
作者:Manfred Braun、Kersten Opdenbusch
DOI:10.1002/jlac.199719970121
日期:1997.1
proven by conversion into the oxazolidinones 16a–d whose optical purity is determined to exceed 92% e.e. by 1H-NMR measurements in the presence of chiralshiftreagents. The sulfonylimine 21a and a series of para-substituted derivatives 21b–h are also allowed to react with the vinyllithium reagent 1b to give mixtures of diastereomers 22/23. The logarithms of the diastereomeric ratios 22:23 correlate with