Further studies of imido alkylidene complexes of tungsten, well-characterized olefin metathesis catalysts with controllable activity
Further studies of imido alkylidene complexes of tungsten, well-characterized olefin metathesis catalysts with controllable activity
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钨亚氨基亚烷基配合物的进一步研究，具有可控活性的表征良好的烯烃复分解催化剂
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发表时间：
1990
期刊：
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通讯作者：
M. Schofield
中科院分区：
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作者：
R. Schrock;R. T. Depue;Jerald Feldman;K. B. Yap;D. Yang;W. M. Davis;L. Y. Park;M. DiMare;M. Schofield
An alternative synthesis of W(CH-t-Bu)(NAr)(dme)Cl{sub 2} (Ar = 2,6-C{sub 6}-H{sub 3}-i-Pr{sub 2}) consists of the five steps WCl{sub 6} {yields} W(O)Cl{sub 4} {yields} W(NAr)Cl{sub 4} {yields} W(NAr)(O-t-Bu){sub 2}Cl{sub 2}(THF) {yields} W(NAr)(O-t-Bu){sub 2}(CH{sub 2}-t-Bu){sub 2} {yields} W(CH-t-Bu)(NAr)(dme)Cl{sub 2}, in which tert-butoxide protecting groups are replaced by chlorides in the last step upon addition of PCl{sub 5}. The easiest synthesis to a catalyst precursor consists of the three steps WO{sub 2}Cl{sub 2} {yields} W(NAr){sub 2}Cl{sub 2}(dme) {yields} W(NAr){sub 2}(CH{sub 2}R){sub 2} {yields} W(CHR)(NAr)(OTf){sub 2}(dme) (R = t-Bu, CMe{sub 2}Ph; OTf = OSO{sub 2}CF{sub 3}), in which an imido ligand protecting group is ultimately replaced by two triflate ligands upon addition of triflic acid in the last step. An X-ray study of W(CH-t-Bu)(NAr)(O-t-Bu){sub 2} shows it to be a pseudotetrahedral complex in which the tert-butyl group points toward the imido ligand.
An alternative synthesis of W(CH-t-Bu)(NAr)(dme)Cl{sub 2} (Ar = 2,6-C{sub 6}-H{sub 3}-i-Pr{sub 2}) consists of the five steps WCl{sub 6} {yields} W(O)Cl{sub 4} {yields} W(NAr)Cl{sub 4} {yields} W(NAr)(O-t-Bu){sub 2}Cl{sub 2}(THF) {yields} W(NAr)(O-t-Bu){sub 2}(CH{sub 2}-t-Bu){sub 2} {yields} W(CH-t-Bu)(NAr)(dme)Cl{sub 2}, in which tert-butoxide protecting groups are replaced by chlorides in the last step upon addition of PCl{sub 5}. The easiest synthesis to a catalyst precursor consists of the three steps WO{sub 2}Cl{sub 2} {yields} W(NAr){sub 2}Cl{sub 2}(dme) {yields} W(NAr){sub 2}(CH{sub 2}R){sub 2} {yields} W(CHR)(NAr)(OTf){sub 2}(dme) (R = t-Bu, CMe{sub 2}Ph; OTf = OSO{sub 2}CF{sub 3}), in which an imido ligand protecting group is ultimately replaced by two triflate ligands upon addition of triflic acid in the last step. An X-ray study of W(CH-t-Bu)(NAr)(O-t-Bu){sub 2} shows it to be a pseudotetrahedral complex in which the tert-butyl group points toward the imido ligand.