224826-10-2Relevant academic research and scientific papers
Mechanistic variety in zirconium-catalyzed bond-forming reaction of arsines
Roering, Andrew J.,Davidson, Jillian J.,MacMillan, Samantha N.,Tanski, Joseph M.,Waterman, Rory
scheme or table, p. 4488 - 4498 (2009/02/04)
Triamidoamine-supported zirconium complexes have been demonstrated to catalyze a range of bond-forming events utilizing arsines. Three different mechanisms have been observed in these reactions. In the first mechanism, triamidoamine-supported zirconium complexes of the general type (N 3N)ZrX (N3N = N(CH2CH2NSiMe 3)33-; X = monoanionic ligand) catalyzed the dehydrogenative dimerization of diphenylarsine. Mechanistic analysis revealed that As-As bond formation proceeds via σ-bond metathesis steps similar to the previously reported dehydrocoupling of phosphines by the same catalysts. In the second mechanism, sterically encumbered primary arsines appear to be dehydrocoupled via α elimination of an arsinidene fragment. Dehydrocoupling of dmpAsH2 (dmp = 2,6-dimesitylphenyl) to form (dmp)As = As(dmp) by (N3N)Zr-complexes appeared to proceed via elimination of dmpAs: from the arsenido intermediate, (N3N)ZrAsH(dmp) . Further support for α-arsinidene elimination came from the thermal decomposition of (N3N)ZrAsHMes (9) to (MesAs)4 (10), which obeyed first-order kinetics. In the third mechanism, the observation of stoichiometric insertion reactivity of the Zr-As bond with polar substrates, PhCH2NC, PhCN, (1-napthyl)NCS, and CS2, led to the development of intermolecular hydroarsination catalysis of terminal alkynes. Here, (N3N)ZrAsPh2 (2) catalyzed the addition of diphenylarsine to phenylacetylene and 1-hexyne to give the respective vinylarsine products. Arsenido complexes 2 and 9 and tetraarsine 10 have been structurally characterized.
