Synthesis and molecular structure of functionalized tris[2-(4′-substituted butoxyphenyl)]phosphine oxides as precursors of tripodal ligands

A series of tris[2-(4′-substituted butoxyphenyl)]phosphine oxides [2-X(CH2)4OC6H4]3PO (X = OAc (2), OH (3), OSO2Me (4), Br (5), and N3 (6)) useful as precursors of new tripodal ligands have been prepared. Alkylation of initial tris(2-hydroxyphenyl)phosphine oxide (1) resulted in triacetate 2, which was deprotected to triol 3. The latter has been converted into trimesylate 4, which has been treated with LiBr or NaN3 to give the corresponding tribromo or triazido derivatives 5 and 6, respectively. According to X-ray diffraction, the molecules of compounds 2, 5, and 6 in crystal adopt conformation where two side arms are oriented to the same direction as the P=O group, while the third side arm is oriented in the opposite manner. © 2018 Wiley Periodicals, Inc.