Abstract Absolute rate studies were carried out on a series of C (SINGLE BOND) H insertion reactions of dimethyldioxirane (1a). The substrates were chosen so that the distance between a single tertiary C (SINGLE BOND) H bond and an OH group could be varied. The measured rate constants indicate that a rate acceleration occurs when the distance between the reacting C (SINGLE BOND) H bond and the OH group permits intramolecular H- ...