首页> 外文期刊>Journal of the American Chemical Society >Synthesis and Evaluation of Molybdenum and Tungsten Monoaryloxide Halide Alkylidene Complexes for Z-Selective Cross-Metathesis of Cyclooctene and Z-1,2-Dichloroethylene
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Synthesis and Evaluation of Molybdenum and Tungsten Monoaryloxide Halide Alkylidene Complexes for Z-Selective Cross-Metathesis of Cyclooctene and Z-1,2-Dichloroethylene

机译:用于环辛烯和Z-1,2-二氯乙烯Z选择性交叉复分解的钼和钨单芳氧基卤化物卤化物亚烷基络合物的合成和评价

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摘要

Molybdenum complexes with the general formula Mo(NR)(CHR')(OR")(Cl)(MeCN) (R = t-Bu or 1-adamantyl; OR" = a 2,6-terphenoxide) recently have been found to be highly active catalysts for cross-metathesis reactions between Z-internal olefins and Z-1,2-dichloroethylene or Z-(CF_3)CH=CH(CF_3). In this paper we report methods of synthesizing new potential catalysts with the general formula M(NR)(CHR')(OR")(Cl)(L) in which M = Mo or W, NR = N-2,6-diisopropylphenyl or NC_6F_5, and L is a phosphine, a pyridine, or a nitrile. We also test and compare all catalysts in the cross-metathesis of Z-1,2-dichloroethylene and cyclooctene. Our investigations indicate that tungsten complexes are inactive in the test reaction either because the donor is bound too strongly or because acetonitrile inserts into a W=C bond. The acetonitrile or pivalonitrile Mo(NR)(CHR')(OR")(Cl)(L) complexes are found to be 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)(CHCMe_2Ph)(OHMT)(Cl)(t-BuCN) (Ar = 2,6-diisopropylphenyl; OHMT = 2,6-dimesitylphenoxide) to give 14e Mo(NAr)(CHCMe_2Ph)(OHMT)Cl in solution as a mixture of syn and anti (60:40 at 0.015 M) nitrile-free isomers, but these 14e complexes have not yet been isolated in pure form. The syn isomer of Mo(Nar)(CHCMe_2Ph)(OHMT)Cl binds pivalonitrile most strongly. Other Mo(NR)(CHR')(OR")(Cl)(L) complexes can be activated through addition of B(C_6F_5)_3. High stereoselectivities (>98% Z,Z) of ClCH=CH(CH_2)_6CH=CHCl are not restricted to tert-butylimido or adamantylimido complexes; 96.2% Z selectivity is observed with boron-activated Mo(NC_6F_5)(CHR')(OHIPT)(Cl)(PPhMe_2). So far no Mo=CHCl complexes, which are required intermediates in the test reaction, have been observed in NMR studies at room temperature.
机译:最近发现具有通式Mo(NR)(CHR')(OR“)(Cl)(MeCN)(R = t-Bu或1-金刚烷基; OR” = 2,6-terphenoxide)的钼配合物是Z-内部烯烃与Z-1,2-二氯乙烯或Z-(CF_3)CH = CH(CF_3)交叉复分解反应的高活性催化剂。在本文中,我们报告了合成通式M(NR)(CHR')(OR“)(Cl)(L)的新型潜在催化剂的方法,其中M = Mo或W,NR = N-2,6-二异丙基苯基或NC_6F_5,并且L是膦,吡啶或腈。我们还测试和比较了Z-1,2-二氯乙烯和环辛烯的交叉复分解中的所有催化剂。我们的研究表明,钨络合物在测试中没有活性反应是因为供体结合得太牢固,或者是因为乙腈插入W = C键。乙腈或新戊腈Mo(NR)(CHR')(OR“)(Cl)(L)配合物特别活泼,因为14e Mo(NR)(CHR')(OR“)Cl核可通过很大程度的腈离解而获得。新戊腈可从Mo(NAr)(CHCMe_2Ph)(OHMT)(Cl )(t-BuCN)(Ar = 2,6-二异丙基苯基; OHMT = 2,6-二甲氧基苯氧基)生成14e Mo(NAr)(CHCMe_2Ph)(OHMT)Cl溶液,为正和反(60:40在0.015 M)无腈异构体但是这些14e配合物尚未以纯净形式分离出来。 Mo(Nar)(CHCMe_2Ph)(OHMT)Cl的同分异构体与新戊腈的结合最牢固。其他Mo(NR)(CHR')(OR“)(Cl)(L)配合物可以通过添加B(C_6F_5)_3来活化。ClCH= CH(CH_2)_6CH的高立体选择性(> 98%Z,Z) = CHCl不限于叔丁基亚氨基或金刚烷基酰亚胺配合物;硼活化的Mo(NC_6F_5)(CHR')(OHIPT)(Cl)(PPhMe_2)观察到96.2%的Z选择性。在室温下的NMR研究中已观察到,它们是测试反应中所需的中间体。

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  • 来源
    《Journal of the American Chemical Society》 |2016年第48期|15774-15783|共10页
  • 作者单位

    Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States;

    Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States;

    Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States;

    Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States;

    Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, Massachusetts 02467, United States;

    Department of Chemistry 6-331, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, United States;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
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