10.1021/om0204686.s001 Detlef Selent Detlef Selent Wolfgang Baumann Wolfgang Baumann Rhett Kempe Rhett Kempe Anke Spannenberg Anke Spannenberg Dirk Röttger Dirk Röttger Klaus-Diether Wiese Klaus-Diether Wiese Armin Börner Armin Börner Reactions of a Hydroxy Phosphonite Ligand in the Coordination Sphere of Rhodium(I) American Chemical Society 2003 phenoxy phosphonite chelate hydroxy phosphonite transformation cleavage bond rhodium bidentate phosphorus ligand phosphite hydroformylation CO hydroxy phosphonite ligand Hydroxy Phosphonite Ligand 2003-10-13 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Reactions_of_a_Hydroxy_Phosphonite_Ligand_in_the_Coordination_Sphere_of_Rhodium_I_/3361495 The complexation behavior of 6-(3,3‘-di-<i>tert</i>-butyl-5,5‘-dimethoxy-2-hydroxy-2‘-oxybiphenyl)-6<i>H</i>-[<i>c</i>,<i>e</i>]-1,2-oxaphosphorine, which generates an active and <i>n</i>-regioselective rhodium(I) catalyst for the isomerizing hydroformylation of internal octenes, was studied. Investigations in the absence of CO/H<sub>2</sub> revealed that coordination of the phenolate moiety of the hydroxy phosphonite on the rhodium center is possible. Interestingly, under conditions related to the hydroformylation (syngas, higher temperature and P:Rh ratios) the ligand suffers two transformations. The first is based on a transesterification reaction involving 2 equiv of the hydroxy phosphonite, giving rise to a substituted biphenol and a symmetric bidentate phosphorus ligand of a heretofore uncertain structure. The second transformation is concerned with a selective Rh(I)-catalyzed P−C bond cleavage of the initial phosphonite structure under the formation of a phosphite. X-ray structural analyses will illustrate the structures of rhodium(I) complexes bearing the original hydroxy phosphonite ligand, a phenoxy phosphonite chelate, and a phosphite formed by selective P−C bond cleavage, respectively.