General Routes to Alkyl Phosphatrioxaadamantane Ligands

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• 作者：Joanne H. Downing ; Joë ; lle Floure ; Katie Heslop ; Mairi F. Haddow ; Jonathan Hopewell ; Matteo Lusi ; Hirahataya Phetmung ; A. Guy Orpen ; Paul G. Pringle ; Robert I. Pugh ; Damaris Zambrano-Williams
• 刊名：Organometallics
• 出版年：2008
• 出版时间：July 14, 2008
• 年：2008
• 卷：27
• 期：13
• 页码：3216 - 3224
• 全文大小：1094K
• 年卷期：v.27,no.13(July 14, 2008)
• ISSN：1520-6041

文摘

The secondary phosphine CgPH (CgP = 6-phospha-2,4,8-trioxa-1,3,5,7-tetramethyladamantyl group) is made in 50% yield by a modification of the literature method (avoiding high pressures of PH₃) by bubbling PH₃ through an acidified solution of 2,4-pentanedione at 0 °C. Under similar conditions the ethyl analogue ^EtCgPH is formed from 3,5-heptanedione in 75% yield. The halophosphines CgPCl and CgPBr are made by treatment of CgPH with N-halosuccinimide. CgPBr is also made by treatment of CgPH with Br₂. Three methods are described for the synthesis of CgPR, where R = alkyl: (a) the previously reported acid-catalyzed condensation reaction of RPH₂ with 2,4-pentanedione, which has been extended to R = ⁱPr; (b) treatment of CgP(BH₃)Li with RX followed by borane deprotection with Et₂NH, which has been used for R = ⁱPr, benzyl, n-C₂₀H₄₁; (c) treatment of CgPBr with RMgX, which has been used for R = ⁱPr, Me. The complexes [PtCl₂(CgPH)₂] (1), [PdCl₂(CgPH)₂] (2), [PdCl₂(CgPR)₂] (where R = ⁱPr (3a), Cy (3b)), and [PtCl₂(CgPR)₂] (where R = ⁱPr (4a), Cy (4b), n-C₂₀H₄₁ (4c)) are described. The crystal structures of CgPH, CgPCl, [CgP(CH₂Ph)₂]Br, CgP(n-C₂₀H₄₁), and complexes 1, 3b, and 4c are reported. From the ν(CO) values for trans-[RhCl(CO)(CgPX)₂], the σ-donor/π-acceptor properties of CgPX are in the order X = ⁱPr > Me > Ph > H > Cl.