通过还原循环策略合成的高活性三烷氧基钼（VI）亚烷基催化剂。

Highly active trialkoxymolybdenum(VI) alkylidyne catalysts synthesized by a reductive recycle strategy.

作者信息

Zhang Wei, Kraft Stefan, Moore Jeffrey S

机构信息

Roger Adams Laboratory, Departments of Chemistry and Materials Science and Engineering, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, USA.

出版信息

J Am Chem Soc. 2004 Jan 14;126(1):329-35. doi: 10.1021/ja0379868.

DOI:10.1021/ja0379868

PMID:14709099

Abstract

A systematic study of alkyne metathesis catalyzed by trialkoxymolybdenum(VI) alkylidyne complexes is reported, in which substrate functional groups, alkynyl substituents, and catalyst ligands are varied. Sterically hindered trisamidomolybdenum(VI) propylidyne complex 5 was prepared conveniently through a previously communicated reductive recycle strategy. Alcoholysis of 5 with various phenols/alcohols provides a set of active catalysts for alkyne metathesis at room temperature, among which the catalyst with p-nitrophenol as ligand shows the highest catalytic activity and is compatible with a variety of functional groups and solvents. A key finding that enabled the use of highly active molybdenum(VI) catalysts is replacement of the commonly used propynyl substituents on the starting alkyne substrates with butynyl groups. Under reduced pressure using 1,2,4-trichlorobenzene as an involatile solvent, the alkyne metathesis of butynyl substituted compounds proceeds well at 30 degrees C providing high yields (83%-97%) of dimers. Rationalization of the special role played by butynyl substrates is discussed.

摘要

本文报道了对三烷氧基钼（VI）亚烷基配合物催化的炔烃复分解反应的系统研究，其中底物官能团、炔基取代基和催化剂配体均有所变化。通过先前报道的还原循环策略方便地制备了空间位阻较大的三氨基钼（VI）丙炔基配合物5。5与各种酚/醇进行醇解反应，可在室温下提供一组用于炔烃复分解反应的活性催化剂，其中以对硝基苯酚为配体的催化剂表现出最高的催化活性，并且与多种官能团和溶剂兼容。使用高活性钼（VI）催化剂的一个关键发现是，用丁炔基取代起始炔烃底物上常用的丙炔基取代基。在减压条件下，以1,2,4 - 三氯苯作为不挥发溶剂，丁炔基取代化合物的炔烃复分解反应在30℃下顺利进行，二聚体产率较高（83% - 97%）。文中讨论了丁炔基底物所起特殊作用的原理。