CHIRAL PHOSPHINE-LIGANDS DERIVED FROM SUGARS .5. CHELATE-STABILIZED ALKOXOPALLADIUM(II) COMPLEXES WITH CHIRAL PHOSPHINE-SUBSTITUTED CARBOHYDRATE LIGANDS

The reactions of chiral P,O-bidentate methyl eoxy-2-(diphenylphosphino )-alpha-D-altropyranoside (HL(1)) and methyl eoxy-3-(diphenylphosphino )-alpha-D-altropyranoside (HL(2)) with [PdCl2(cod)] (cod = cycloocta-1 ,5-diene) or [PdCl2(NCMe)(2)] gave the complexes trans-[PdCl2(HL)(2)] (L = L(1) 1a or L(2) 1b). Complex 1b crystallizes in the tetragonal sp ace group P4(1)2(1)2, with a = 12.326(2), c = 32.649(8) Angstrom and Z = 4, R = 0.023 for 2502 reflections having I greater than or equal to 3 sigma(1). The large deviation (14.6 degrees) of the angle P-Pd-P' f rom 180 degrees may be ascribed to the overcrowding of the bulky phosp hine ligands. Treatments of 1a and 1b with NaOMe in methanol gave the corresponding bis(alkoxo) complexes cis-[PdL(2)] 2a and 2b. The compou nds have been characterized by infrared, Raman, H-1, C-13 and P-31 NMR spectroscopy. The Pd-O absorption appears at 388 cm(-1) for 2a and 36 6 cm(-1) for 2b. The cis and trans geometries have been assigned by Ra man spectroscopic studies.