The 1,3-elimination occurred preferentially from the carbonyl side of chiral camphorpyrazolidinone, leading to the formation of the major diastereoisomer. Diazo acetamide, 3d goes in similar mechanism, except in situ generated ylide (Fig. ). In most of the cases trans structure was assigned to the major compound with the help of 1 H NMR spectroscopy and ORTEP.