Synthesis and study of amino acid based phosphinite ligands

The preparation of the five new amino acid derived phosphinites Boc-Ser(OPPh2)-OMe (5), Boc-Thr(OPPh2)-OMe (6), Boc-Tyr(OPPh2)-OMe (7), Z-Ser(OPPh2)-OMe (8), and Z-β-Ala-Tyr(OPPh2)-OMe (9) is reported together with their full spectroscopic characterization. These ligands readily complex to Pd(II) and Pt(II) giving the corresponding complexes [Boc-Ser(OPPh2)-OMe]2PtCl2 (10), [Boc-Tyr(OPPh2)-OMe]2PtCl2 (11), [Boc-Thr(OPPh2)-OMe]2PtCl2 (12), [Z-β-Ala-Tyr(OPPh2)-OMe]2PtCl2 (13), [Boc-Ser(OPPh2)-OMe]2PdCl2 (14), [Boc-Tyr(OPPh2)-OMe]2PdCl2 (15), [Boc-Thr(OPPh2)-OMe]2PdCl2 (16), [Z-β-Ala-Tyr(OPPh2)-OMe]2PdCl2 (17). The X-ray structure of 10 was determined and shows the ligands being cis coordinated around the Pt(II) center with PtP distances of 2.2278(13) Å for PtP(1) and 2.2235(12) Å for PtP(2).