Asymmetric Reductive Amination of Cycloalkanones, VII: Asymmetric Synthesis of cis-1R,2R- and cis-1S,2S,-2-Arylcyclohexanamines

Article abstract of DOI:10.1002/ardp.19893220402

The asymmetric synthesis of cis-2-arylcyclohexanamines 4 by a three-step procedure is reported: condensation of racemic 2-arylcyclohexanones 1 with the chiral auxiliary R-(+)- or S-(-)-1-phenylethylamine, respectively, leads to a mixture of the imin isomers 2.Upon hydrogenation with Raney-Nickel just one secondary amin of type 3 is obtained, which is hydrogenolyzed to the optically active primary cis-2-arylcyclohexanamines 4.The relative configuration as well as the conformation were derived from 1H-NMR data.The absolute configuration of the highly enantiomericallypure compounds 4 was determined by CD spectra.