Access to 1-aryl-pyrazolin-5-ones via photoinduced chemoselective cyclization of N-methacrylo aldehyde hydrazones

A photocatalytic sulfamoylation/5-endo-trig cyclization of (E)-N'-arylidene-N-phenylmethacrylohydrazides with sulfamoyl chlorides was developed. The chemoselective intramolecular addition of the carbon-centered radical intermediate to the C=N bond in hydrazone motif gave the sulfamoylated...