Inversion of Configuration at the Metal in Diastereomeric Imido Alkylidene Monoaryloxide Monopyrrolide Complexes of Molybdenum

被引:44
作者
Marinescu, Smaranda C. [1 ]
Schrock, Richard R. [1 ]
Li, Bo [2 ]
Hoveyda, Amir H. [2 ]
机构
[1] MIT, Dept Chem 6 331, Cambridge, MA 02139 USA
[2] Boston Coll, Dept Chem, Merkert Chem Ctr, Chestnut Hill, MA 02467 USA
基金
美国国家卫生研究院; 美国国家科学基金会;
关键词
TOPOLOGICAL REPRESENTATION; METATHESIS; STEREOISOMERISM; PSEUDOROTATION; CATALYSTS;
D O I
10.1021/ja808308e
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The two diastereomers of Mo(NAr)(CHCMe2Ph)(2,5-dimethylpyrrolide)(1), (SMR1)-2 and (RMR1)-2, respectively, where 1 is an enantiomericatly pure (R) phenoxide and Ar = 2,6-diisopropylphenyl, form adducts with PMe3. One of these ((RMR1)-2(PMe3)) has been isolated. An X-ray structure reveals that PMe3 has added trans to the pyrrolide; it is a model for where an olefin would attack the metal. Trimethylphosphine will catalyze slow interconversion of (SMR1)-2 and (RMR1)-2 via formation of weak PMe3 adducts. Reactions between (SMR1)-2 or (RMR1)-2 and ethylene yield Mo(NAr)(CH2)(Me(2)Pyr)(1) species in which the configuration at Mo is inverted by ethylene at a rate of the order of the NMR time scale at 22 degrees C via formation of metallacyclobutane intermediates with imido and aryloxide ligands in axial positions. A reactant olefin is proposed to approach Mo and the product otefin to leave Mo trans to the pyrrolide.
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页码:58 / +
页数:4
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