Highly Stereoselective Syntheses of syn- and anti-1,2-Amino Alcohols
摘要:
The reduction of N-protected amino ketones can be carried stereoselectively to produce either the syn- or anti-amino alcohol diastereomer. Carbamate-protected amino ketones can be reduced predictably and selectively to anti-amino alcohols with LiAlH(O-t-BU)(3) in ethanol at -78 degreesC. N-Trityl-protected amino ketones can be reduced selectively to syn-amino alcohols with LiAlH(O-t-Bu)(3) in THF at -5 degreesC.
A Stereocontrolled Synthesis of Monofluoro Ketomethylene Dipeptide Isosteres
作者:Robert V. Hoffman、Junhua Tao
DOI:10.1021/jo981334y
日期:1999.1.1
A simple, stereocontrolled synthesis of monofluoro ketomethylene dipeptideisosteres has been developed. N-Tritylated ketomethylene dipeptideisosteres, prepared from N-tritylated amino acids, are converted to their Z-TMS enol ethers and fluorinated with Selectfluor. There is cooperative stereocontrol between the N-tritylamine group and the alkyl group at C-2. The method is short (six steps), diastereoselective