Mechanism of Catalytic Nitrene Transfer Using Iron(I)-Isocyanide Complexes

作者：Cowley Ryan E; Golder Matthew R; Eckert Nathan A; Al Afyouni Malik H; Holland Patrick L^*

来源：Organometallics, 2013, 32(19): 5289-5298.

DOI：10.1021/om400379p

Low-spin iron(I) complexes supported by bulky beta-diketiminate ligands catalyze the formation of unsymmetric carbodiimides (RN=C=NR', R not equal R') from isocyanides and organoazides. In situ EPR studies indicate that the catalytic resting state in these reactions is the tris(isocyanide)iron(I) complex LFe(CNR)(3), and kinetic experiments show that the reaction is inverse second-order in isocyanide concentration, suggesting that two isocyanide molecules dissociate prior to the rate-determining step. An unusual iron carbodiimide complex can be isolated independently, and facile displacement of the coordinated carbodiimide by both isocyanide and N-2 demonstrate that product release is not kinetically limiting during catalysis. These experimental data fit a coherent mechanism for the catalytic C-N coupling reaction, and the implications for catalytic nitrene transfer are discussed.

• 出版日期2013-10-14