To understand the anoxic thiyl chemistry, the kinetic analysis of the reaction was investigated at a specified time of the reaction. First, the rate of the reaction was almost first-order with respect to the concentrations of both maleate and radical initiator, while a zeroth-order dependence was observed with respect to the concentration of thiols (Fig. ). The maleate dependence differs from previous works on acid or thiourea-catalyzed isomerization, in which the kinetic models revealed a 1.5-2-order dependence on the maleate concentration. Because the radical initiators did not expedite the reaction catalytically (Fig. and Table entry 13), the concentration dependence indicates the importance of radical activation of either the thiols or reaction intermediates.