Reactivity Studies of a T-Shaped Yttrium Carbene: C鈥揊 and C鈥揙 Bond Activation and C鈺怌 Bond Formation Promoted by [Y(BIPM)(I)(THF)2] (BIPM = C(PPh2NSiMe3)2)

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• 作者：David P. Mills ; William Lewis ; Alexander J. Blake ; Stephen T. Liddle
• 刊名：Organometallics
• 出版年：2013
• 出版时间：March 11, 2013
• 年：2013
• 卷：32
• 期：5
• 页码：1239-1250
• 全文大小：574K
• 年卷期：v.32,no.5(March 11, 2013)
• ISSN：1520-6041

文摘

The yttrium carbene complex [Y(BIPM)(I)(THF)₂] (1; BIPM = C(PPh₂NSiMe₃)₂) was reacted with a range of unsaturated substrates. The reaction of 1 with the phosphaalkyne PCBup>tp> afforded the [2 + 2] cycloaddition product [Y{C(PPh₂NSiMe₃)₂(PCBup>tp>)-魏p>4p>C,C鈥?N,N鈥瞹(I)] (2). Similarly, the reactions of 1 with the heteroallenes N,N鈥?dicyclohexylcarbodiimide and tert-butyl isocyanate gave the [2 + 2] cycloaddition products [Y{C(PPh₂NSiMe₃)₂[C(NCy)₂]-魏p>4p>C,N,N鈥?N鈥硙(I)(THF)] (3) and [Y{C(PPh₂NSiMe₃)₂[C(O)(NBup>tp>)]-魏p>4p>C,N,N鈥?O}(I)(THF)₂] (4), respectively. In contrast, the reaction of 1 with tert-butyl isothiocyanate afforded the ketenimine Bup>tp>N鈺怌鈺怌(PPh₂NSiMe₃)₂ (5), with the concomitant formal elimination of 鈥淵SI(THF)_n鈥? The sterically demanding arylamine 2,6-diisopropylphenylamine reacted with 1 via a 1,2-addition across the Y鈺怌 bond to yield the anilide鈥搈ethanide complex [Y(BIPMH)(NHDipp)(I)(THF)] (6; Dipp = C₆H₃Prp>ip>₂-2,6). The reaction of 1 with the benzopyrone coumarin affords the ring-opened dinuclear aryloxide鈥揺nolate complex [Y₂{C(PPh₂NSiMe₃)₂[C(O)(CHCHC₆H₄O-2)]-魏p>2p>-N,O:渭,魏-O鈥瞹₂(I)(渭-I)(THF)] (7), which is postulated to form by sequential Y鈥揙, C鈥揅, and C鈺怌 bond formation and cleavage of the C鈥揙 ester linkage and the C鈺怬 and Y鈺怌 double bonds. Benzoyl fluoride reacts with 1 to afford p>1p>/₂ equiv of the bis-enolate complex [Y{C(PPh₂NSiMe₃)₂[C(O)(Ph)]-魏p>2p>N,O}₂(I)] (8) with formal elimination of 鈥淵F₂I(THF)_n鈥?by ligand scrambling. Complexes 2鈥?b>8 have been characterized by X-ray crystallography, multielement NMR spectroscopy, FTIR spectroscopy, and CHN microanalyses.