Synthesis and Reactivity of o-Phosphane Oxide Substituted Aryl(hydro)borates and Aryl(hydro)boranes
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- 作者：Jens Michael Breunig ; Felix Lehmann ; Michael Bolte ; Hans-Wolfram Lerner ; Matthias Wagner
- 刊名：Organometallics
- 出版年：2014
- 出版时间：June 23, 2014
- 年：2014
- 卷：33
- 期：12
- 页码：3163-3172
- 全文大小：419K
- ISSN：1520-6041
文摘
The reaction of 1,2-C6H4(P(O)-t-Bu2)(Li) (Ph*Li) with B(OMe)3 furnishes a mixture of Li[Ph*B(OMe)3] (Li[2a]) and Ph*B(OMe)2 (2b). Further treatment with Li[AlH4] provides the trihydroborate Li[Ph*BH3] (Li[3]), which can subsequently be converted into the intramolecular P鈺怬鈥揃 adduct Ph*BH2 (4) through hydride abstraction with Me3SiCl. Addition of C6F5MgBr yields Mg[Ph*BH2(C6F5)]2 (Mg[5]2), which is inert toward Me3SiCl but reacts with water to give Ph*B(H)C6F5 (6). Upon addition of further C6F5MgBr, a mixture is formed, from which crystals of Mg[Ph*BH(C6F5)2]2 (Mg[7]2) were obtained. The reaction of Ph*Li with (C6F5)2BH路SMe2 provides access to Li[7], but again with limited product selectivity. The targeted acidic hydrolysis of Li[7] furnishes Ph*B(C6F5)2 (8), while Mg[7]2 reacts back to 6. The anions of the hydroborates Li[3] and Mg[5]2 act as BH2,O-chelating ligands toward their metal ions. Therefore, Li[Ph*2BH2] (Li[13]) was also synthesized to obtain the corresponding pincer-type species. 4, 6, and 8 exist as water-stable intramolecular P鈺怬鈥揃 adducts both in solution and in the solid state. X-ray crystallography and 31P NMR spectroscopy indicate an increase in the Lewis acidity of the boryl groups in the order 4 < 6 < 8.