Transition structures for the stepwise insertion of oxygen into alkane tertiary C-H bonds by dimethyldioxirane

Oxygen insertion into the isobutane C-H bond by dimethyldioxirane 1 was com putationally studied at the R(U)B3LYP level to address the mechanistic conc erted-stepwise problem. We located genuine TSs, diradicaloid in nature, tha t can lead to final products via radical pair intermediates. These TSs have lower energies than their concerted counterpart. Thus, calculations suppor t the viability of radical pair formation in the reaction of dioxiranes wit h alkanes. (C) 2001 Elsevier Science Ltd. All rights reserved.