Phosphine Oxazoline Ligands Research Articles

Synthesis of a class of new phosphine-oxazoline ligands and their applications in palladium-catalyzed asymmetric addition of arylboronic acids to isatins

A class of new phosphine-oxazoline ligands was prepared from commercially available and inexpensive starting materials. As the first example, in situ formed catalysts generated from chiral phosphine-oxazolines and Pd(OAc)2 were successfully applied to the asymmetric addition reactions of arylboronic acids to isatins, and 3-aryl-3-hydroxyoxindoles were obtained in up to 97% yields and good enantioselectivities (up to 88% ee). Up to 98% enantiopurity of the products were obtained after one recrystallization.

Bis(perfluoroalkyl) Phosphino-Oxazoline: A Modular, Stable, Strongly π-Accepting Ligand for Asymmetric Catalysis

A new class of stable, strongly π-accepting and modular bis(perfluoroalkyl)-phosphine-oxazoline ligands (FOX) as CO mimics was prepared. It was demonstrated that these ligands, when coordinated to palladium catalysts, promote the asymmetric alkylation of monosubstituted allyl substrates with excellent regio- and enantioselectivity. Solid and solution structure analysis of the FOX-ligated Pd-allyl intermediate reveals that the combination of relative steric and strong trans influences presented by the P(CF(3))(2) moiety gave rise to the excellent selectivity.

ChemInform Abstract: Recent Advances in Transition Metal Catalyzed Enantioselective Hydrogenation of Unprotected Enamines

AbstractReview: 71 refs.

Enantioselective iridium-catalyzed hydrogenation of α-arylcinnamic acids and synthesis of (S)-equol

By using iridium catalyst based on chiral spiro phosphine–oxazoline ligands, the hydrogenation of α-arylcinnamic acids was accomplished under ambient pressure and low catalyst loading (as low as 0.01 mol %), providing useful 2,3-diarylpropionic acids in high yields with excellent enantioselectivities (up to 99% ee). A catalytic enantioselective synthesis of (S)-equol with the present hydrogenation reaction as a key step was accomplished starting from commercially available starting materials in six steps with 48.4% overall yield.

Recent advances in transition metal-catalyzed enantioselective hydrogenation of unprotected enamines

Transition metal-catalyzed enantioselective hydrogenation of enamines is undoubtedly a useful and environment-friendly method for the preparation of optically pure chiral amines and amine derivatives. Over the last few decades, the use of transition metal catalysts containing chiral phosphorus or phosphine-oxazoline ligands attracted much attention for the hydrogenation of unprotected enamines. A number of efficient chiral catalysts have been developed, and some of them have shown high potential for the application in the synthesis of optical chiral amines in both laboratory and industry. This tutorial review focuses on the contributions concerning the transition metal-catalyzed enantioselective hydrogenation of unprotected enamines for the synthesis of chiral amines and amine derivatives.

Iridium-catalyzed asymmetric hydrogenation of 3-substituted unsaturated oxindoles to prepare C3-mono substituted oxindoles

An efficient and enantioselective hydrogenation of 3-substituted unsaturated oxindoles has been developed by an iridium complex of tropos phosphine–oxazoline ligands. It is the first example to prepare chiral C3-mono substituted oxindoles via asymmetric catalysis. And the reaction provides instant access to this kind of compounds with excellent conversion and enantioselectivities (up to 93% ee).

ChemInform Abstract: Axially Chiral Phosphine—Oxazoline Ligands in Silver(I)‐Catalyzed Asymmetric Mannich Reaction of N‐Boc Aldimines with Trimethylsiloxyfuran.

AbstractAmong 12 chiral binaphthylphosphines, (Ra)‐BOP is the best ligand in the reaction with imine (IIb).

ChemInform Abstract: Highly Diastereo‐ and Enantioselective Vinylogous Mannich Reactions of Fluorinated Aldimines with Siloxyfurans.

A highly regio- and enantioselective asymmetric vinylogous Mannich reaction of readily available fluorinated aldimines bearing a chiral auxiliary [(S)-1-phenylethyl group] with siloxyfurans to afford chiral fluorine-containing γ-butenolide or γ-lactone derivatives has been developed in the presence of silver acetate (10 mol%) and axially chiral phosphine-oxazoline ligand L1 (11 mol%). In most cases, the corresponding fluorinated adducts were obtained in high yields, good to excellent enantiomeric excesses and up to > 20:1 dr.

Axially chiral phosphine–oxazoline ligands in silver(I)-catalyzed asymmetric Mannich reaction of N-Boc aldimines with trimethylsiloxyfuran

Axially chiral phosphine–oxazoline ligand L6 was found to be a fairly effective chiral ligand in silver(I)-catalyzed asymmetric Mannich reaction of N-Boc aldimines with trimethylsiloxyfuran to give the corresponding adducts in up to 97% yield, 7:1 dr and 86% ee (major diastereoisomer).

ChemInform Abstract: Iridium‐Catalyzed Asymmetric Hydrogenation of Olefins Using TIQ Phosphine—Oxazoline Ligands.

AbstractThe title reaction affords high enantiomeric excesses but also a high substrate dependence is observed.

Palladium-catalyzed 1,4-addition of diarylphosphines to α,β-unsaturated N-acylpyrroles

Highly stereoselective asymmetric 1,4-addition of diarylphosphines to α,β-unsaturated N-acylpyrroles catalyzed by a PCP pincer-Pd complex has been developed for the synthesis of chiral phosphines with excellent stereoselectivity (91-99% ee) under mild conditions. The products obtained can be further converted into chiral phosphine-oxazoline ligands.

Convenient synthesis of tropos phosphine-oxazoline ligands

Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis. Here we present a convenient and economic route for the synthesis of this type of ligands. According to this new route, the ligands with different electronic and steric properties have been prepared successfully.

ChemInform Abstract: Iridium‐Catalyzed Highly Enantioselective Hydrogenation of Exocyclic α,β‐Unsaturated Carbonyl Compounds.

By using the iridium complex of a phosphine-oxazoline ligand with an axis-unfixed biphenyl backbone, a highly enantioselective hydrogenation of the C=C bond of exocyclic α,β-unsaturated carbonyl compounds to afford α-chiral cyclic ketones, lactones and lactams was developed.

Iridium-Catalyzed Asymmetric Hydrogenation of Exocyclic Ketones, Lactones, and Lactams

The authors discovered a very efficient iridium-catalyzed process for asymmetric hydrogenation of exocyclic α,β-unsaturated carbonyl compounds using axis-unfixed phosphine oxazoline ligands. Five-membered exocyclic α,β-unsaturated ketones, lactones, and lactams were hydrogenated to generate corresponding α-chiral carbonyl compounds in high conversion and enantioselectivities.

ChemInform Abstract: Axially Chiral Phosphine—Oxazoline Ligands in the Silver(I)‐Catalyzed Asymmetric Mannich Reaction of Fluorinated Aldimines with Trimethylsiloxyfuran.

ChemInformVolume 41, Issue 49 Heterocyclic Compounds ChemInform Abstract: Axially Chiral Phosphine—Oxazoline Ligands in the Silver(I)-Catalyzed Asymmetric Mannich Reaction of Fluorinated Aldimines with Trimethylsiloxyfuran. Qian-Yi Zhao, Qian-Yi Zhao Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this authorZhi-Liang Yuan, Zhi-Liang Yuan Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this authorMin Shi, Min Shi Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this author Qian-Yi Zhao, Qian-Yi Zhao Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this authorZhi-Liang Yuan, Zhi-Liang Yuan Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this authorMin Shi, Min Shi Inst. Fine Chem., East China Univ. Sci. Technol., Shanghai 200237, Peop. Rep. ChinaSearch for more papers by this author First published: 11 November 2010 https://doi.org/10.1002/chin.201049093Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume41, Issue49December 7, 2010 RelatedInformation

Iridium-catalyzed asymmetric hydrogenation of olefins using TIQ phosphine–oxazoline ligands

A novel family of tetrahydroisoquinoline (TIQ) phosphine–oxazoline ligands and four corresponding iridium complexes have been developed and applied to the asymmetric hydrogenation of unfunctionalized olefins. The results showed that the best conversion rates were observed in up to 99% with an enantiomeric excess of 91%.

ChemInform Abstract: Design and Optimization of New Phosphine Oxazoline Ligands via High-Throughput Catalyst Screening.

This paper uses the phosphine oxazoline ligands 1 and an allylation transformation (reaction 1) to illustrate the value of divergent ligand syntheses and high-throughput screening in catalyst discovery and optimization. Thus, a diverse set of ligands 1 (Table 1) was prepared via a divergent synthesis involving the pivotal intermediate, phosphine-substituted amino alcohol 7 (Scheme 1). Single-crystal X-ray crystallographic data was obtained for a nickel complex 8 (Figure 3) of the phenyl-substituted ligand 1i. This analysis illustrated some structural features of the ligand systems 1 that may be conducive to asymmetric catalysis. High-throughput screens were then used to correlate the ligand 1 R-substituents with asymmetric induction in the allylation reaction 1, and it emerged that the pseudo-spherical adamantyl substituent was superior to other R-substituents. Other parameters in the catalyst systems were also varied, sometimes in “two-dimensional” screens. No pronounced solvent effects were identified. ...

Axially chiral phosphine–oxazoline ligands in the silver(I)-catalyzed asymmetric Mannich reaction of fluorinated aldimines with trimethylsiloxyfuran

Axially chiral phosphine–oxazoline ligand L7, prepared from ( S)-binol, was found to be a fairly effective chiral ligand in the silver(I)-catalyzed asymmetric Mannich reaction of fluorinated aldimines with trimethylsiloxyfuran to give the corresponding adducts in up to 99% yield, over 20:1 dr and 81% ee.

Axially Chiral Phosphine-Oxazoline Ligands in Silver(I)- Catalyzed Asymmetric Mannich Reaction of Aldimines with Trimethylsiloxyfuran

A new asymmetric catalytic system for the Mannich reaction of aldimines with trimethylsiloxyfuran is described. The combination of an axially chiral phosphine-oxazoline ligand (S)-2-[(R)-2'-(diphenylphosphino)-1,1'-binaphthyl-2-yl]-4-phenyl-4,5-dih ydrooxazole with silver acetate and 2,2,2-trifluoroacetic acid is a very effective catalytic system in the asymmetric Mannich reaction of various aldimines with trimethylsiloxyfuran in dichloromethane at -78 degrees C, affording the corresponding adducts in up to 99% yield, 99:1 (dr) and 99% ee (major diastereoisomer) under mild conditions.

Phosphine-oxazoline ligands with an axial-unfixed biphenyl backbone: the effects of the substituent at oxazoline ring and P phenyl ring on Pd-catalyzed asymmetric allylic alkylation

A novel kind of chiral phosphine-oxazoline ligands 3 with an axial-unfixed biphenyl backbone bearing different substituent on oxazoline ring and P phenyl ring was prepared. These ligands exist as a mixture of two diastereomers in equilibrium in solution. Upon coordinated to Pd(II), however, only one of the two possible kinds of diastereomer complexes with different axial chirality was formed. These compounds as chiral ligands were applied in Pd-catalyzed asymmetric allylic alkylation with high reaction activity and enantioselectivity. Meanwhile, the asymmetric catalytic behavior was affected obviously by the substituent at oxazoline ring and P phenyl ring. The best result, up to 92.3% ee and 99% yield, was obtained with the ligand 3c having two phenyl groups on P and a phenyl group on oxazoline ring in this asymmetric catalysis reaction.