Cyclization/hydrolysis of 1,5-enenitriles initiated by sulfonyl radicals in the aqueous phase in the presence of the I 2 /TBHP system.

A novel cyclization/hydrolysis of 1,5-enenitriles for the synthesis of valuable pyrrolidine-2,4-diones in the aqueous phase using I 2 as the catalyst and tert -butyl hydroperoxide (TBHP) as the oxidant is reported. In the presence of the I 2 /TBHP system, sulfonyl hydrazides produce sulfonyl radicals, which undergo radical addition, intramolecular cyclization, hydrogen abstraction, and hydrolysis to give the final products. The use of the inexpensive and environmentally friendly I 2 /TBHP catalytic oxidation system in the aqueous phase makes it a benign and sustainable strategy.