Process for preparation of chiral cis-3,4-substituted pyrrolidine compounds having the formulas: ##STR1## and chiral 3,4-trans-substituted pyrrolidine compounds having the formulas: ##STR2## with the assistance of a streochemically directing chiral oxazolidinone moiety having the formula: ##STR3## wherein P, R and R.sup.1 are specifically defined, by sequential reaction of the compound or subsequent intermediates with an a,b-unsaturated add chloride, reaction with N-benzyl-N-(methoxymethyl)trimethyl-silylmethylamine and separating isomers by chromatography, hydrolytic removal of the oxazolidinone moiety, reaction with diphenylphosphoryl azide and triethylamine, and debenzylating; and novel intermediates of the process.