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Pyridine-based N-phosphanylamidine ligands i-Pr2N–C(pyr) N–PR2 (R = Ph (3), i-Pr (4)) were synthesized and fully characterized by NMR spectroscopy and X-ray crystallography. Mononuclear rhodium complexes 7 and 8 were obtained in one step from the [RhCl(COD)]2 dimer and the monodentate ligands 1 and 2. Their single-crystal X-ray diffraction studies revealed the structural adaptive behavior of the monodentate N-phosphanylamidine ligands 1 and 2 upon k1-P coordination mode in rhodium(I) complexes with the imino nitrogen atom of the amidine function which behaves as a “universal joint”. Compounds 1–4 were evaluated as ligands in the 1-octene and styrene hydroformylation reactions. The results obtained are encouraging and represent the first report on the use of N-phosphanylamidine ligands of the type R″2N–C(R′) N–PR2 in catalytic reactions.

The four complexes [Pd(H)(Cl)L 2 ] and [Pd(H)(SnCl 3 )L 2 ], L = PPh 3 , PCy 3 , have been synthesized and fully characterized by multinuclear NMR. They represent the active species of the hydride palladium-catalyzed alkoxycarbonylation of terminal alkenes. Isolation of the model acylplatinum complex, resulting from the carbonylation of dihydromyrcene, clearly shows that SnCl 2 as co-catalyst produces a SnCl 3 ligand which modulates the metal center electron density.

The methoxycarbonylation of dihydromyrcenol 1 has been carried out in the presence of the catalytic system [PdCl2(PPh3)2]–SnCl2·2H2O–2PPh3. This study shows that it is possible to reduce the amounts of isomerization of the terminal double bond and the dehydration side-reaction of the tertiary alcoholic function. According to the experimental conditions (PCO=40 or 100 bar, concentration of methanol, experiment duration, temperature) it is possible to orient the reaction towards the three ‘linear’ esters 4, 5, 6, and lactone 8. This latter product has been exclusively obtained when the acidity of the medium is controlled. Nevertheless it is more difficult to obtain one ester from each others.