Ethene Elimination during Thermolysis of Bis(3-butenyltetramethylcyclopentadienyl)dimethyltitanium

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• 作者：Jir虒i&#769 ; Pinkas ; Ro虂bert Gyepes ; Jir虒i&#769 ; Kubis虒ta ; Michal Hora虂č ; ek ; Karel Mach
• 刊名：Organometallics
• 出版年：2011
• 出版时间：May 9, 2011
• 年：2011
• 卷：30
• 期：9
• 页码：2581-2586
• 全文大小：832K
• 年卷期：v.30,no.9(May 9, 2011)
• ISSN：1520-6041

文摘

Thermolysis of [TiMe₂{畏⁵-C₅Me₄(CH₂CH₂CH鈺怌H₂)}₂] (1) in toluene at 120 掳C for 4 h resulted in the formation of the cyclopentadiene ring-tethered titanacyclobutane [Ti^IV{畏⁵-C₅Me₄CH₂CH₂CH(魏-CH)}₂CH₂] (2) in virtually quantitative yields. Thermolysis in an NMR tube at 100 掳C revealed that initial elimination of methane is followed by addition of one 3-butenyl double bond to a titanocene鈭抦ethylidene moiety. The formed titanacyclobutane intermediate [Ti{畏⁵-C₅Me₄(CH₂CH₂CH鈺怌H₂)}{畏⁵-C₅Me₄CH₂CH₂CH(魏-CH)CH₂CH₂(魏-CH₂)}] (4) then underwent a metathesis reaction with the pendant 3-butenyl to give 2 and free ethene. Cleavage of Ti鈭扖 bonds of 2 with HCl afforded stable ansa-[TiCl₂{畏⁵-C₅Me₄(CH₂)₇畏⁵-C₅Me₄}] (3). Sunlight photolysis of 1 gave rise to the cyclopentadiene ring-tethered titanacyclopentane [Ti^IV{畏⁵-C₅Me₄(CH₂CH₂CH(魏-CH)CH₂}₂] (5), the known product of cycloaddition reactions following the removal of chlorine atoms from [TiCl₂{畏⁵-C₅Me₄(CH₂CH₂CH鈺怌H₂)}₂] with magnesium (as found by Hora膷ek, M. Chem. Eur. J. 2000, 6, 2397).