Abstract The Michael addition of optically active 3, 4-diphenyloxazolidinone 5 to 2′- substituted 2-chloro-2-cyclopropylideneacetates yields 2′-substituted 2-cyclopropyl-1′-(2- oxo-3, 4-diphenyloxazolidin-3-yl) acetates 6-R with excellent trans-selectivity, which upon reductive dehalogenation and subsequent hydrogenolysis give free 2-(1′-amino- cyclopropyl) acetic acids 9.