Highly Regioselective Isomerization–Hydroformylation of Internal Olefins Catalyzed by Rhodium/Tetraphosphine Complexes

Abstract A new class of substituted tetraphosphine ligands has been applied in the rhodium‐catalyzed regioselective isomerization–hydroformylation of internal olefins. The rhodium/tetraphosphine ligand system is highly effective for the isomerization and hydroformylation of 2‐alkenes to form linear aldehydes. Greater than 95% linear selectivity and up to 94% yield of the total aldehydes were obtained for 2‐pentene, 2‐hexene and 2‐octene. The catalyst system also showed high to moderate linear selectivity for the isomerization and hydroformylation of 3‐hexene, 3‐octene and 4‐octene but with slow reaction rates.