Synthesis of Spiro[pyrazolin-3,3′-oxindoles] and 3‑Arylcarbonylmethyl Substituted Ylideneoxindoles by 1,3-Dipolar Cycloadditions of 3‑Ylideneoxindoles and In-Situ-Generated α‑Diazoketones

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
scopes as well as without using any transition metal catalyst.