The radical pair mechanism in hydrometalation and stoichiometric hydrogenation reactions of dicarbonyl(cyclopentadienyl)iron hydride [.eta.5-C5H5Fe(CO)2H] with conjugated dienes

The hybride η 5 -C 5 H 5 Fe(CO) 2 H reacts with a variety of 1,3-dienes to form both the products of irreversible 1,4-addition of the hydride to the diene and of stoichiometric hydrogen transfer to the diene. The hydrometalation reactions are first order in both η 5 -C 5 H 5 Fe(CO) 2 H and diene and zero order in added carbon monoxide, while use of η 5 -C 5 H 5 Fe(CO 2 )D shows that the reaction exhibits an inverse primary isotope effect