Al/P-Based Frustrated Lewis Pairs: Limitations of Their Synthesis by Hydroalumination and Formation of Dialkylaluminum Hydride Adducts

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• 作者：Werner Uhl ; Christian Appelt ; Jana Backs ; Hauke Westenberg ; Agnes Wollschl盲ger ; Jens Tannert
• 刊名：Organometallics
• 出版年：2014
• 出版时间：March 10, 2014
• 年：2014
• 卷：33
• 期：5
• 页码：1212-1217
• 全文大小：278K
• 年卷期：v.33,no.5(March 10, 2014)
• ISSN：1520-6041

文摘

Aluminum鈥損hosphorus-based frustrated Lewis pairs (Al/P FLPs) are valuable reagents for the dipolar activation or coordination of small molecules or ionic compounds. They are accessible by hydroalumination of alkynylphosphines. However, as reported in this article, the application of this simple method for the synthesis of a broad variety of different compounds is limited to sterically shielded systems. Hydroalumination of Mes₂PC鈮Ph with small dialkyl- or diarylaluminum hydrides HAlR₂ (R = Me, iBu, Ph) afforded unique adducts in which an HAlR₂ molecule was coordinated by the Al/P FLP Mes₂PC(鈺怌HPh)AlR₂ via an Al鈥揚 and an Al鈥揌鈥揂l 3c bond. A new Al/P FLP was obtained with equimolar quantities of dineopentylaluminum hydride. The less shielded alkynylphosphine Ph₂PC鈮Ph yielded a hydride adduct with HAlNp₂ and an alkyne adduct with HAltBu₂. The latter compound resulted from triple-bond activation and had a five-membered AlPC₃ heterocycle in which a C鈺怌 bond was bonded to the P and Al atoms of an Al/P FLP. Both compounds were isolated in high yields by application of the appropriate stoichiometric ratios of the starting materials.