Synthesis and Evaluation of Molybdenum and Tungsten Monoaryloxide Halide Alkylidene Complexes for Z-Selective Cross-Metathesis of Cyclooctene and Z-1,2-Dichloroethylene was written by Lam, Jonathan K.;Zhu, Congqing;Bukhryakov, Konstantin V.;Muller, Peter;Hoveyda, Amir;Schrock, Richard R.. And the article was included in Journal of the American Chemical Society in 2016.Category: pyridine-derivatives This article mentions the following:
Mo complexes Mo(NR)(CHR’)(OR)(Cl)(MeCN) (R = t-Bu or 1-adamantyl; OR = a 2,6-terphenoxide) recently are highly active catalysts for cross metathesis reactions between Z-internal olefins and Z-1,2-dichloroethylene or Z-(CF3)CH:CH(CF3). The authors report methods of synthesizing new potential catalysts M(NR)(CHR’)(OR)(Cl)(L) in which M = Mo or W, NR = N-2,6-diisopropylphenyl or NC6F5, and L is a phosphine, a pyridine, or a nitrile. The catalysts are tested in the cross-metathesis of Z-1,2-dichloroethylene and cyclooctene. The studies indicate that W complexes are inactive in the test reaction either because the donor is bound too strongly or because MeCN inserts into a W:C bond. The MeCN or pivalonitrile Mo(NR)(CHR’)(OR)(Cl)(L) complexes are especially reactive because the 14e Mo(NR)(CHR’)(OR)Cl core is accessible through dissociation of the nitrile to a significant extent. Pivalonitrile can be removed (>95%) from Mo(NAr)(CHCMe2Ph)(OHMT)(Cl)(t-BuCN) (Ar = 2,6-diisopropylphenyl; OHMT = 2,6-dimesitylphenoxide) to give 14e Mo(NAr)(CHCMe2Ph)(OHMT)Cl in solution as a mixture of syn and anti (60:40 at 0.015M) nitrile-free isomers, but these 14e complexes have not yet been isolated in pure form. The syn iso-mer of Mo(NAr)(CHCMe2Ph)(OHMT)Cl binds pivalonitrile most strongly. Other Mo(NR)(CHR’)(OR)(Cl)(L) complexes can be activated through addition of B(C6F5)3. High stereoselectivities (>98% Z,Z) of ClCH:CH(CH2)6CH:CHCl are not restricted to t-butylimido or adamantylimido complexes; 96.2% Z selectivity is observed with B-activated Mo(NC6F5)(CHR’)(OHIPT)(Cl)(PPhMe2). So far no Mo:CHCl complexes, which are required intermediates in the test reaction, were observed in NMR studies at room temperature In the experiment, the researchers used many compounds, for example, Pyridinehydrochloride (cas: 628-13-7Category: pyridine-derivatives).
Pyridinehydrochloride (cas: 628-13-7) belongs to pyridine derivatives. In contrast to benzene, Pyridine’s electron density is not evenly distributed over the ring, reflecting the negative inductive effect of the nitrogen atom. Several pyridine derivatives play important roles in biological systems. While its biosynthesis is not fully understood, nicotinic acid (vitamin B3) occurs in some bacteria, fungi, and mammals.Category: pyridine-derivatives