Chiral (Diphosphonite)platinum Complexes in Asymmetric Hydroformylation |
| |
| Authors: | Ruben van&#x;Duren Leandra&#x;L&#x;J&#x;M Cornelissen Jarl&#x;Ivar van&#x;der&#x;Vlugt Jeroen&#x;P&#x;J Huijbers Allison&#x;M Mills Anthony&#x;L Spek Christian Müller Dieter Vogt |
| |
| Institution: | Ruben van Duren,Leandra L. J. M. Cornelissen,Jarl Ivar van der Vlugt,Jeroen P. J. Huijbers,Allison M. Mills,Anthony L. Spek,Christian Müller,Dieter Vogt |
| |
| Abstract: | The chiral diphosphonite ligand (11bR,11′bR)‐4,4′‐(9,9‐dimethyl‐9H‐xanthene‐4,5‐diyl)bisdinaphtho2,1‐d:1′,2′‐f]1,3,2]dioxaphosphepin] ((R,R)‐XantBino; (R)‐ 1 ), based on a rigid xanthene backbone, was applied in the Pt/Sn‐catalyzed hydroformylation of styrene ( 4a ), 4‐methylstyrene ( 4b ), vinyl acetate ( 4c ), and allyl acetate ( 4d ), by using a Pt/Sn ratio of 1 : 1. High ee of up to 80% were observed, along with good regioselectivities towards the desired branched aldehydes. For styrene, an interesting inversion in the stereoselection process was observed at elevated temperatures, and a mechanism is proposed considering the temperature dependence of the regioselectivity. The complex PtCl2{(S,S)‐XantBino}] ((S)‐ 2 ) was characterized by X‐ray crystal‐structure analysis, revealing an unusual out‐of‐plane ligand coordination of the metal fragment. The complex PtCl(SnCl3){(R,R)‐XantBino}] ((R)‐ 3 ) was characterized by means of 31P‐NMR spectroscopy. |
| |
| Keywords: | Hydroformylation Diphosphonite ligand chiral Platinum complexes Enantioselectivity Catalysis |
|
|
