Towards the synthesis of perfluoroalkylated derivatives of Xantphos

Adams, Dave J.; Cole‐Hamilton, David J.; Harding, Duncan A. J.; Hope, Eric G.; Pogorzelec, Peter J.; Stuart, Alison M.

doi:10.1016/j.tet.2004.02.070

Cited by 23 publications

(14 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As expected, the productivity (TON = turnover number) decreases with increasing pressure, as the coordination of styrene to the metal center requires dissociation of carbon monoxide. Compared to reaction rates with Xantphos [34], the increased activity of this type of catalyst agrees well with the higher accessibility of the metal due to the 'out-of-plane' Pt-center. The lower linear-tobranched ratio supports this even further.…”

Section: Results Andsupporting

confidence: 56%

Chiral (Diphosphonite)platinum Complexes in Asymmetric Hydroformylation

Duren

Cornelissen

Vlugt

et al. 2006

Helvetica Chimica Acta

View full text Add to dashboard Cite

Dedicated to Professor Giambattista Consiglio on the occasion of his 65th birthdayThe chiral diphosphonite ligand (11bR,11'bR)-4,4'-(9,9-dimethyl-9H-xanthene-4,5-diyl)bis[dinaphtho[2,1-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. Introduction. -The asymmetric hydroformylation of alkenes is a reaction of great potential for the production of optically active aldehydes, which are versatile building blocks in synthetic organic chemistry [1] [2]. Initial work on asymmetric hydroformylation in the presence of cobalt [3], platinum [4], and rhodium catalysts [5] resulted in very low enantioselectivities, but the Pt/Sn-catalyst, modified with chiral diphosphine ligands and pioneered by Consiglio and co-workers led to much better results than any previous system [6]. However, these catalysts showed poor regioselectivities, yielding the branched, chiral aldehydes in only 50 -70% and in some cases of up to 80% [7]. Additionally, the formation of hydrogenated products and double-bond isomerization as unwanted side reactions were observed.Typically, a large excess of up to 6 equiv. of SnCl 2 was necessary to form stable catalysts and to avoid decomposition to Pt-black. However, this excess causes significant product racemization, as observed problem for the early systems, leading to lower overall enantioselectivities [6]. To overcome these drawbacks, trapping agents, e.g., triethyl orthoformate (HC(OEt) 3 ) were added, to achieve in situ protection of the aldehyde and to reach high enantioselectivities of up to 96% [8] [9]. Alternatively, preformation of the Pt/Sn bimetallic catalyst species resulted in higher enantioselectivities as well as chemo-and regioselectivities [10] [11].

show abstract

Section: Results Andsupporting

confidence: 56%

Chiral (Diphosphonite)platinum Complexes in Asymmetric Hydroformylation

Duren

Cornelissen

Vlugt

et al. 2006

Helvetica Chimica Acta

View full text Add to dashboard Cite

show abstract

“…2-Phenoxy-1-phenylethanol, 1 6,7-bis(diphenyl- proceedures. [4][5][6][7][8] All reagents were purchased from commercial suppliers and used as received, unless otherwise noted. NMR spectra were obtained on a Bruker AVANCE III 500 spectrometer.…”

Section: General Experimentalmentioning

confidence: 99%

Electronic and bite angle effects in catalytic C–O bond cleavage of a lignin model compound using ruthenium Xantphos complexes

Shaw

Somisara

How

et al. 2017

Catal. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…The solubility was increased easily by adding alkyl chains R 1 and R 2 to ligand 35 to give 36, which did not deteriorate the catalytic performance. Compared to other wide-bite-angle diphosphine ligands, Xantphos-type ligands can be modified easily while retaining there favorable properties, especially in hydroformylation, and as a result many derivatives have been synthesized and used in fluorous-phase hydroformylation catalysis [72], aqueous-phase catalysis [73,74], one-phase hydroformylation and catalyst extraction [75], catalysis in ionic liquids [76,77], hydroformylation with immobilized catalysts [78,79], and catalysis in supercritical CO 2 [80].…”

Section: Mechanistic Studiesmentioning

confidence: 99%