W(O-2,6-C6H3X2)2Cl4/Bu4Sn as metathesis catalyst of 1-alkenes
摘要:
Tungsten compounds with aryloxo ligands, i.e., W(O-2,6-C6H3X2)(2)Cl-4 (X = Cl,Ph) and Bu,Sn, were investigated as catalytic systems for the metathesis of l-alkenes of varying carbon lenghts. The catalytic system was activated at 85 degrees C for 20 min prior to use. Optimum metathesis activity with l-alkenes was observed at 85 degrees C and a Sn/W molar ratio = 3. The W(O-2,6-C6H3X2)(2)Cl-4/Bu4Sn catalytic system is very active for the metathesis of l-alkenes with a carbon chain length of about six to eight and it favours a more polar solvent such as chlorobenzene. (C) 1998 Elsevier Science B.V. All rights reserved.
Synthesis and catalytic properties of W(OAr)2Cl2(CHCMe3)(OR2) and W(OAr)2Cl(CHCMe3)(CH2CMe3)(OR2)(Ar = 2,6-disubstituted phenyl; R = Et or Pri), new uni-component catalysts for metathesis of acyclic and cyclic olefins, with or without functional groups
The synthesis of W(OAr)2Cl(CHR)(CH2R1)(OR22)(Ar = 2,6-disubstitutedphenyl; R2= Et or Pri) illustrates one of the first examples of a well defined, Lewis acid free, homogeneous olefin metathesis catalyst, for which the activity and stereoselectivity can be governed by the nature of the aryloxide ligands and of the co-ordinated ether and which shows a wide range of potential applications.
W(OAr)2 Cl(CHR)(CH 2 R 1)(OR 2 2)(Ar = 2,6-二取代苯基; R 2 = Et或Pr i)的合成说明了孔的第一个例子定义为无路易斯酸的均相烯烃复分解催化剂,其活性和立体选择性可以由芳基氧化物配体和配位醚的性质决定,并显示出广泛的潜在应用。
Kerschner, Judith L.; Rothwell, Ian P.; Huffman, John C., Organometallics, 1988, vol. 7, # 8, p. 1871 - 1873
作者:Kerschner, Judith L.、Rothwell, Ian P.、Huffman, John C.、Streib, William E.
DOI:——
日期:——
Kerschner, Judith L.; Fanwick, Philip E.; Rothwell, Ian P., Organometallics, 1989, vol. 8, # 6, p. 1431 - 1438
作者:Kerschner, Judith L.、Fanwick, Philip E.、Rothwell, Ian P.、Huffman, John C.
作者:Quignard, Francoise、Leconte, Michel、Basset, Jean-Marie、Hsu, Leh-Yeh、Alexander, John J.、Shore, Sheldon G.
DOI:——
日期:——
The metathesis of polyunsaturated fatty esters using the homogeneousW(O-2,6-C6H3X2)2Cl4/Me4Sn catalytic systems
作者:B Marvey
DOI:10.1016/j.molcata.2003.11.026
日期:2004.4.13
Promoted with a small amount of Me4Sn, W(O-2,6-C6H3X2)(2)Cl-4 (X = Ph, Cl) complexes are highly active metathesis catalysts for polyunsaturated fatty esters. Upon metathesis of methyl linoleate, substrate conversions of ca. 95 and 78% were obtained in 2h with the W(O-2,6-C6H3Ph2)(2)Cl-4/Me4Sn and W(O-2,6-C6H3Cl2)(2)Cl-4/Me4Sn catalytic systems respectively. ne lower activity of the W(O-2,6-C6H3Cl2)(2)Cl-4/Me4Sn catalytic system was attributed to the highly deactivating nature of the Cl substituents on the o,o'-position of the aryloxide ligand. Highly electron-withdrawing Cl substituents cause the tungsten atom to be electron-deficient and thus more susceptible to attack by the electron-rich ester groups. However, the W(O-2,6-C6H3Cl2)(2)Cl-4/Me4Sn system was more selective towards dicarboxylic esters. The latter are interesting starting materials for the synthesis of polyesters and polyamides. The W(O-2,6-C6H3X2)(2)Cl-4/Me4Sn catalytic systems were rapidly deactivated by bromine-containing olefinic esters. Deactivation was attributed to a side reaction between the Br-group and the electron-deficient W-centre. (C) 2003 Elsevier B.V. All rights reserved.