ENANTIOSELECTIVE SYNTHESIS OF A STERICALLY HINDERED AMINE

摘要

Compounds of the formula (I) wherein R is phenyl, or phenyl substituted by Cl, Br, C₁-C₄alkyl or CF₃; R₁ is H or methyl or ethyl; R₂ is H or methyl or acyl; R₃ is H or methyl; R'₄ is -CH₃ or =CH₂; may be obtained in high enantiopurity by hydrogenation of a compound of the formula (II) wherein R and R₃ are as in formula (I); A is acyl; and R₄ is -CH₃ or =CH₂; in the presence of a chiral Rhodium or Ruthenium catalyst. Residues R₁ as methyl or ethyl and/or R₂ as H or methyl may subsequently be introduced without racemization by deacylation and optional alkylation.