Addition to electron deficient olefins of alpha-oxy carbon- centered radicals, generated from cyclic ethers and acetals by the reaction with alkylperoxy- lambda(3)-iodane.

Thermal decomposition of 1-tert-butylperoxy-1,2-benziodoxol-3(1H)-one in cyclic ethers and acetals at 50 degrees C generates alpha-oxy carbon-centered radicals, which undergo an addition reaction with vinyl sulfones and unsaturated esters.