active r enantiomer the present process will yield the r r diastereoisomer the stereochemistry of the diastereoisomer compounds x is referenced with regard to the two optically active centers for this compound str5 the term 34 alkyl 34 including the alkyl portions of alkoxy represents a straight or branched saturated hydrocarbon chain preferably having from 1 to 6 carbon atoms such as methyl ethyl isopropyl n propyl n butyl t butyl pentyl hexyl and the like the term 34 aryl 34 represents a carbocyclic group having from 6 to 14 carbon atoms and having at least one fused benzenoid ring with all available substitutable carbon atoms of the carbocyclic group being intended as possible points of attachment preferred aryl groups are phenyl 1 naphthyl 2 naphthyl and indanyl the term 34 substituted aryl 34 refers to said carbocyclic group being optionally substituted with 1 to 3 moieties independently selected from halo alkyl alkoxy or nitro representative substituted aryl groups include methylphenyl chlorophenyl 1 methylnapthyl and the like cyanide compounds of the formula m 1 c tbd n iii wherein m 1 is hydrogen trimethylsilyl or a metal which can be sodium potassium lithium cesium iron nickel cadmium and zinc are well known compounds suitable cyanide reagents include hydrogen cyanide hcn trimethylsilyl cyanide cnsi ch 3 3 iron dicyanide fe cn 2 cadmium dicyanide cd cn 2 zinc dicyanide zn cn 2 sodium cyanide nacn lithium cyanide licn cesium cyanide cscn and potassium cyanide kcn preferably sodium cyanide and potassium cyanide the lewis acid compounds of formula iv are well known compounds as defined in j march advanced organic chemistry reactions mechanisms and structure 3rd edition john wiley amp sons new york 1985.