文摘
Under H2, the radical cyclization of appropriate dienes can be catalyzed by cobaloximes. H鈥?can be abstracted from an intermediate (presumably a cobalt hydride) by trityl radicals (Ar3C鈥? or by TEMPO. The rate-determining step in these reactions is the uptake of H2, which is second order in cobalt and first order in hydrogen; the third-order rate constant is 106(3) M鈥?路s鈥?.