The scope and generality of this addition protocol was investigated (Table ). A wide range of α,β-unsaturated amides used tested and found that unsubstituted 2a, gives mixture of diastereomers 3a, 3b respectively. the major diastereomers 3a is 1S based on steric grounds that carbenes like dichlorocarbene would approach the double bond from the side opposite to that of the N-phenyl substituent on chiral pyrazolidinone. The beta phenyl substituent 2b converted to β-phenyl substituted esters in beta-phenyl single diastereomer 4a with 61% yield . The -ester 2c did not give the product, the n-propyl 2d and methyl 2e substituents gives single diastereomer 5a and 6a in 62 and 67 % yield, respectively. Further the 6a structure was confirmed by single x-ray crystals, where methyl group is trans to chiral amide, the trans orientations of starting material remains intact, it indicates that dichloro carbene is in singlet state and reaction proceeds in single step. The presence of additional carbons as branched chain at beta position, isopropyl 2f, tertiary butyl 2g and b,b-substituents 2h, motifs did retard the desired spiro reaction (for 3f-3h). The presence of a bulky β-aryl group that can destabilize the resulting alkyl radical intermediates was envisioned to account for the above no reaction selectivitively.