this invention relates to a process for preparing optically active α - amino acid substrates which are used to make potent lethal factor inhibitors for the treatment of anthrax . this invention further relates to a process for synthesis of potent lf - inhibitors for the treatment of anthrax . specifically , the invention concerns a novel , high - yielding and highly enantioselective asymmetric hydrogenation reaction of a tetrasubstituted ene - sulfonamide acid or ester .