Reactions of a Hydroxy Phosphonite Ligand in the Coordination Sphere of Rhodium(I)

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• 作者：Detlef Selent ; Wolfgang Baumann ; Rhett Kempe ; Anke Spannenberg ; Dirk Rö ; ttger ; Klaus-Diether Wiese ; and Armin Bö ; rner
• 刊名：Organometallics
• 出版年：2003
• 出版时间：October 13, 2003
• 年：2003
• 卷：22
• 期：21
• 页码：4265 - 4271
• 全文大小：136K
• 年卷期：v.22,no.21(October 13, 2003)
• ISSN：1520-6041

文摘

The complexation behavior of 6-(3,3'-di-tert-butyl-5,5'-dimethoxy-2-hydroxy-2'-oxybiphenyl)-6H-[c,e]-1,2-oxaphosphorine, which generates an active and n-regioselective rhodium(I)catalyst for the isomerizing hydroformylation of internal octenes, was studied. Investigationsin the absence of CO/H₂ revealed that coordination of the phenolate moiety of the hydroxyphosphonite on the rhodium center is possible. Interestingly, under conditions related tothe hydroformylation (syngas, higher temperature and P:Rh ratios) the ligand suffers twotransformations. The first is based on a transesterification reaction involving 2 equiv of thehydroxy phosphonite, giving rise to a substituted biphenol and a symmetric bidentatephosphorus ligand of a heretofore uncertain structure. The second transformation isconcerned with a selective Rh(I)-catalyzed P-C bond cleavage of the initial phosphonitestructure under the formation of a phosphite. X-ray structural analyses will illustrate thestructures of rhodium(I) complexes bearing the original hydroxy phosphonite ligand, aphenoxy phosphonite chelate, and a phosphite formed by selective P-C bond cleavage,respectively.