An efficient 1,3-dipolar cycloaddition of 3-ylideneoxindoles with in-situ-generated α-diazoketones to potentially biological active spiro[pyrazolin-3,3′-oxindoles] 4 with excellent regioselectivity and diastereoselectivity and synthetically useful building block 3-arylcarbonylmethyl substituted ylideneoxindoles 5 in different conditions has been developed. This method has advantages of mild conditions, simple workup, and wide substrate sco...