Unraveling the Bite Angle Effect: New Ligands for Selective Hydroformylation of Internal Alkenes
Tóm tắt
Rhodium catalyzed hydroformylation is one of the most important applications of homogeneous catalysis in industry[1]. The addition of CO and H2 to alkenes is a mild and clean method for the functionalization of hydrocarbons. The atom economy of the reaction can be 100% and the selectivity for the desired aldehyde can be very high. Most of the six million tons of aldehydes produced annually by this process is converted into plasticizers for polymers and detergent alcohols. Since the linear aldehydes are the desired products for these applications, a key issue in industrial hydroformylation is the control of regioselectivity. The generally accepted hydroformylation mechanism is shown in Scheme 1. The active catalyst is the five-coordinated complex A, which usually contains two phosphorus ligands. This catalyst consists of two isomeric structures in which the phosphine ligands coordinate in a diequatorial (e-e) and in an equatorial-apical (e-a) fashion. Bidentate ligands can give rise to either of these two complexes depending on their natural bite angle.
Tài liệu tham khảo
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