Alkylation and Insertion Reactions in Dichloro Azatantalacyclopropane Complexes. X-ray Crystal Structures of [TaCpCl2{C(Ph)CHCMe2NAr-g src="http://pubs.acs.org/images/gifchars

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• 作者：Mikhail V. Galakhov ; Manuel G&oacute ; mez ; Pilar G&oacute ; mez-Sal ; and Patricia Velasco
• 刊名：Organometallics
• 出版年：2005
• 出版时间：February 28, 2005
• 年：2005
• 卷：24
• 期：5
• 页码：848 - 856
• 全文大小：213K
• 年卷期：v.24,no.5(February 28, 2005)
• ISSN：1520-6041

文摘

Dichloro azatantalacyclopropane complexes [TaCpCl₂(CMe₂NAr-G SRC="/images/gifchars/kappa.gif" BORDER=0 >²C,N)] (Ar = 2,6-Me₂C₆H₃;Cp = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅, 1; ges/gifchars/eta.gif" BORDER=0 >⁵-C₅H₄SiMe₃, 2) can be obtained by treating TaCpCl₂Me₂ with 1 equiv of2,6-dimethylphenylisocyanide. Alkylation of 1 with an excess of MgCl(CH₂SiMe₃) leads to[TaCp*Cl(CH₂SiMe₃)(CMe₂NAr-ges/gifchars/kappa.gif" BORDER=0 >²C,N)] (Cp* = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅; Ar = 2,6-Me₂C₆H₃, 3), which insolution slowly decomposes to give [TaCp*Cl{C(Me)=CH₂}(NAr)] (Cp* = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅;Ar = 2,6-Me₂C₆H₃, 4) with elimination of SiMe₄. The same reaction with other alkylatingreagents takes place with the formation of 4, although we have not observed similarintermediate monoalkyl derivatives. The complexes 1 and 2 react with ethylene to give thedichloro azatantalacyclopentane compounds [TaCpCl₂(CH₂CH₂CMe₂NAr-ges/gifchars/kappa.gif" BORDER=0 >²C,N)] (Ar = 2,6-Me₂C₆H₃; Cp = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅, 5; ges/gifchars/eta.gif" BORDER=0 >⁵-C₅H₄SiMe₃, 6). However, benzene-d₆ solutions of 5 and 6decompose at room temperature to give a dichloro(imido) tantalum complex [TaCpCl₂(NAr)](Ar = 2,6-Me₂C₆H₃, Cp = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅, 7;ges/gifchars/eta.gif" BORDER=0 >⁵-C₅H₄SiMe₃, 8) with elimination of 2-methyl-2-butene(Me₂C=CH-Me) and 3-methyl-1-butene (H₂C=CH-CHMe₂) (decomposition of 5) and only2-methyl-2-butene (decomposition of 6). The complex [TaCp*Cl₂{CH₂CH(Me)CMe₂NAr-ges/gifchars/kappa.gif" BORDER=0 >²C,N}] (Cp* = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅; Ar = 2,6-Me₂C₆H₃, 9) was detected by NMR spectroscopy aftertreatment of 1 with propylene in dichloromethane-d₂. The analogous reaction of 1 or 2 withalkynes RCges/entities/tbd1.gif">CH (R = H, Ph, SiMe₃) leads to the formation of the dichloro azatantalacyclopentene complexes [TaCpCl₂(CRCHCMe₂NAr-ges/gifchars/kappa.gif" BORDER=0 >²C,N)] (Ar = 2,6-Me₂C₆H₃; Cp = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅Me₅,R = H, 10; Ph, 11; SiMe₃, 12; Cp = ges/gifchars/eta.gif" BORDER=0 >⁵-C₅H₄SiMe₃, R = H, 13; Ph, 14; SiMe₃, 15), the processbeing regioselective when monosubstituted alkynes RCges/entities/tbd1.gif">CH (R = Ph, SiMe₃) were used. Allthe new compounds were studied by IR and NMR spectroscopy, and the molecular structuresof complexes 11 and 14 were determined by X-ray diffraction methods.