Synthesis and complexation of novel dibenzo[c.e][1,2]oxaphosphorine-based P-ligands

The reaction of chloro-dibenzo[c.e][1,2]-oxaphosphorine with (L)-methyl prolinate gave the corresponding phosphorous ester-amide, while the interaction of the same starting material with half an equivalent of 2-methylaminothanol and (1S,2R)-(+)-ephedrine led to the corresponding bis(dibenzooxaphosphorine) derivatives that are bidentate P-ligands. The new P-ligands prepared were characterized as the corresponding P-borane and P-oxide derivatives. The P-ligands were utilized in the synthesis of novel Pt-complexes, which gave a species of PtCl₂P₂ type, while two others were seven-membered chelate ring complexes. Structures of the Pt-complexes were elucidated on the basis of stereospecific J _Pt–P couplings and quantum chemical calculations.