Abstract: The catalytic epoxidation of various olefins with iodosylbenzene is efficiently carried out by a series of chromium (II1) cations Cr"'(salen)+(I) which are promoted by pyridine N-oxide (py0) and related oxygen donors as the cocatalyst. Analysis of the catalytic rate profile and products establish the oxochromium (V) derivative O= Cr (salen)+(11) and its donor adduct O= Cr (salen)(pyO)+(111) as the reactive intermediates in the catalytic cycle. ...
