A series of palladium(II) complexes incorporating 1-substituted-3-methyl-3-
phospholenes as the P-ligands were prepared from phospholene oxides by deoxygenation
followed by complexation with PdCl2(PhCN)2. The two 1-substituted-3-methyl-3-
phospholene ligands were trans position to each other in the Pd(II)-complexes. As the
ligands contain a P-stereogenic center, the Pd-complexes were obtained as a 1:1 mixture
of two stereoisomers, the homochiral (R,R and S,S) and the meso (R,S) forms, when racemic
starting materials were used. An optically active Pd-complex containing (R)-1-propyl-
3-phospholene ligand was also prepared. Catalytic activity of an aryl- and an alkyl-3-
phospholene-palladium(II)-complex was evaluated in hydroalkoxycarbonylation of
styrene. The alkyl-derivative showed higher activity and selectivity towards the formation
of the esters of 3-phenylpropionic acid. However, the overall activity of these PdCl2(phospholene)2-type
complexes was low.
Keywords: 3-Phospholene oxides, deoxygenation, 3-phospholenes, palladium complexes, hydroalkoxycarbonylation.
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