Stereochemistry of Imino Group Reduction. 2. Synthesis and Assignment of Configuration of Some N-(1-Phenylethyl)-1,2-diaryl-2-aminoethanols.

Article abstract of DOI:10.1021/jo00329a018

Lithium aluminum hydride reduction of the monoimines prepared by reaction of benzils and 1-phenylethylamine yields a mixture of the related diastereomeric N-(1-phenethyl)-1,2-diaryl-2-aminoethanols.After separation of the diastereomers, assignment of their configuration is made on the basis of their infrared and NMR spectra.Catalytic hydrogenation of the monoimine prepared from benzil yields the amino ketone, which when treated with lithium aluminum hydride yields a mixture of aminoethanols.The composition of this shows that the stereochemical result of this reduct-ion is different from that of the direct reduction.Stereochemical results are analyzed on he basis of models which take into account different initial conformations of the monoimine and the higher probability of attack of hydride at the less hindered side of each conformer.