Substituent Effects on Reactions of [RhCl(COD)]2 with Diazoalkanes

Article abstract of DOI:10.1021/acs.organomet.8b00889

The reactions of [RhCl(COD)]₂ with a series of diazoalkanes with different substitutents were investigated. The outcomes of the reactions were found to be substituent-dependent via four different pathways. (1) The reactions with diazoindenes produced ??⁵-cyclopentadienyl complexes. (2) The reaction with diazofluorene produced a mixture of olefin and azine compounds. (3) The reactions with monosubstituted diazoalkanes RCHN₂ (R = Ph, MeO₂C) produced olefins RCHa?CHR. (4) The reaction with the disubstituted diazoalkane Ph₂CN₂ produced the azine Ph₂Ca?N-Na?CPh₂ only. Computational studies have been carried out to understand the interesting substituent effect by comparing the kinetics and thermodynamics of the reaction pathways. It was found that the reactions with diazocyclopentadiene, diazoindene, and Ph₂CN₂ are kinetically controlled, while the reactions with RCHN₂ and diazofluorene are both thermodynamically and kinetically controlled.