Rh(II) catalysts with 4-hydroxyproline-derived ligands

Bonge, Hanne Therese; Kaboli, Massoud; Hansen, Tore

doi:10.1016/j.tetlet.2010.07.115

Cited by 12 publications

(10 citation statements)

References 14 publications

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“…Fortunately, a partial, and simple, solution is available through the facile conversion of trans -4-hydroxy-L-proline to its diastereomer cis -4-hydroxy-D-proline, a conversion that has been studied and modified for more than 60 years [ 72 ]. Treatment of trans -4-hydroxy-L-proline with acetic anhydride under heating, followed by hydrolysis in dilute hydrochloric acid, gives cis -4-hydroxy-D-proline·HCl via an N -acetylated lactone [ 73 ], a product that can be acylated directly in the same manner as the natural hydroxyproline ( Scheme 14 ) [ 48 , 74 ]. In addition to acrylic proline monomers [ 48 ], the O -acylation of cis -4-hydroxy-D-proline (albeit not the hydrochloride salt in this case) has also been employed as a key step in the preparation of ligands for new chiral Rh(II) catalysts ( Scheme 14 ) [ 74 ].…”

Section: Reviewmentioning

confidence: 99%

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Kristensen¹

2015

Beilstein J. Org. Chem.

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SummaryAmino acids, whether natural, semisynthetic or synthetic, are among the most important and useful chiral building blocks available for organic chemical synthesis. In principle, they can function as inexpensive, chiral and densely functionalized starting materials. On the other hand, the use of amino acid starting materials routinely necessitates protective group chemistry, and in reality, large-scale preparations of even the simplest side-chain derivatives of many amino acids often become annoyingly strenuous due to the necessity of employing protecting groups, on one or more of the amino acid functionalities, during the synthetic sequence. However, in the case of hydroxyamino acids such as hydroxyproline, serine, threonine, tyrosine and 3,4-dihydroxyphenylalanine (DOPA), many O-acyl side-chain derivatives are directly accessible via a particularly expedient and scalable method not commonly applied until recently. Direct acylation of unprotected hydroxyamino acids with acyl halides or carboxylic anhydrides under appropriately acidic reaction conditions renders possible chemoselective O-acylation, furnishing the corresponding side-chain esters directly, on multigram-scale, in a single step, and without chromatographic purification. Assuming a certain degree of stability under acidic reaction conditions, the method is also applicable for a number of related compounds, such as various amino alcohols and the thiol-functional amino acid cysteine. While the basic methodology underlying this approach has been known for decades, it has evolved through recent developments connected to amino acid-derived chiral organocatalysts to become a more widely recognized procedure for large-scale preparation of many useful side-chain derivatives of hydroxyamino acids and related compounds. Such derivatives are useful in peptide chemistry and drug development, as amino acid amphiphiles for asymmetric catalysis, and as amino acid acrylic precursors for preparation of catalytically active macromolecular networks in the form of soluble polymers, crosslinked polymer beads or nanoparticulate systems. The objective of the present review is to increase awareness of the existence and convenience of this methodology, assess its competitiveness compared to newer and more elaborate procedures for chemoselective O-acylation reactions, spur its further development, and finally to chronicle the informative, but poorly documented history of its development.

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Section: Reviewmentioning

confidence: 99%

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Kristensen¹

2015

Beilstein J. Org. Chem.

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“…[6][7][8][9] The catalytic results depended on the N-sulfonyl functionalities of the rhodium(II) prolinate complexes. [6][7][8][9] The catalytic results depended on the N-sulfonyl functionalities of the rhodium(II) prolinate complexes.…”

Section: Resultsmentioning

confidence: 99%

“…6 The Davies group developed the n-dodecyl substituted complex Rh 2 (S-DOSP) 4 , which can be dissolved in pentane even at −78°C and displayed especially high asymmetric induction in the reactions of a variety of donor/acceptor carbenoids, including cycloaddition such as cyclopropanation, cyclopropenation, [3 + 2] annulation, tandem cyclopropanation/Cope rearrangement, and three component coupling, 7 and X-H insertion such as carbenoid C-H insertions, combined C-H activation/ Cope rearrangement, and tandem ylide formation/[2,3]-sigmatropic rearrangement. 9 The hydroxyl groups were O-acylated with acid chlorides such as lauroyl chloride and cyclohexylcarbonyl chloride. 9 The hydroxyl groups were O-acylated with acid chlorides such as lauroyl chloride and cyclohexylcarbonyl chloride.…”

Section: Introductionmentioning

confidence: 99%

Chiral dirhodium catalysts derived from l-serine, l-threonine and l-cysteine: design, synthesis and application

et al. 2015

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A series of dirhodium tetrakis((4S)-3-(arylsulfonyl)oxazolidine-4-carboxylate), dirhodium tetrakis((4S,5R)-5-methyl-3-(arylsulfonyl)oxazolidine-4-carboxylate) and dirhodium tetrakis((4R)-3-(arylsulfonyl)thiazolidine-4-carboxylate 1,1-dioxide) complexes with different para-substituted arylsulfonyl groups (e.g. -NO 2 , -F, -CF 3 , -Me, -t Bu, -OMe and -n C 12 H 25 ) derived from L-serine, L-threonine and L-cysteine, respectively, were prepared with yields in the range of 40-87% through refluxing ligands in water with Na 4 Rh 2 (CO 3 ) 4 . These chiral Rh(II) complexes have been fully characterized by EA, IR, UV-vis, NMR and specific rotation measurements. They are found to be effective chiral catalysts for asymmetric aziridination and cyclopropanation reactions in terms of reactivity and enantioselectivity. They are extremely stable and can be stored for a long period (at least 18 months) on the bench without adversely affecting their reactivity and selectivity. The heterocyclic rings as well as the substituents on the arylsulfonyl groups have critical effects on the degree of asymmetric induction. In general, a higher enantioselectivity was observed in the reactions catalyzed by the oxazolidine-4-carboxylate-derived catalysts than the thiazolidine-4-carboxylate 1,1-dioxide-based catalysts. Among these 21 new Rh(II) catalysts, the uses of dirhodium tetrakis((4S)-3-((4-dodecylphenyl)sulfonyl)oxazolidine-4-carboxylate) (Rh 2 (4S-DOSO) 4 ) and dirhodium tetrakis-((4S,5R)-5-methyl-3-((4-nitrophenyl)sulfonyl)oxazolidine-4-carboxylate) (Rh 2 (4S,5R-MNOSO) 4 ) resulted in the highest levels of enantioselectivity in aziridination (94% ee) and cyclopropanation (98% ee) of styrene, respectively. The successful design and syntheses of these novel Rh(II) complexes enlarged the scope of accessible chiral dirhodium(II) catalysts. † Electronic supplementary information (ESI) available: NMR spectra of the ligands and Rh(II) complexes; CIF files giving crystallographic data. CCDC 1055407 and 1038152. For ESI and crystallographic data in CIF or other electronic format see

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“…6). In the work of Bonge et al [37], a three new chiral Rh(II) catalysts with 4-hydroxyproline-derived ligands were synthesized by using the high temperature ligand exchange method [32] with Rh 2 (OAc) 4 (Fig. 7).…”

Section: A Mckervey Et Almentioning

confidence: 99%

“…Chiral dirhodium(II) catalysts derived from enantiomerically pure -carboxamidates ligands were initially developed by Doyle and co-workers [7,[32][33][34][35][36][37][38][39][40][41][46][47][48][49][50]. Later on, the range of complexes has been expanded to include a greater diversity of a variety of ligands (73-83) (i.e., Pyrrolidinone, oxazolidinones, imidiazolidinone, and azetidinone) and ligand substituents.…”

Section: Dirhodium Carboxamidate Complexesmentioning

confidence: 99%

Chiral Dirhodium Catalysts: A New Era for Asymmetric Catalysis

El‐Deftar¹,

Adly²,

Gardiner

et al. 2012

COC

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The catalysis by dirhodium paddlewheel complexes has been an area of immense interest and extensive study over the past three decades -not only because most of the catalysts are highly stable to heat, moisture and ambient atmosphere but also for the asymmetric induction in the ylide generation. In this review, we attempt to provide an overview on the general preparation method for most homogeneous chiral dirhodium(II) catalysts that have appeared to date and their recent applications in asymmetric catalysis with iodonium ylides as carbenoid precursors.

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Rh(II) catalysts with 4-hydroxyproline-derived ligands

Cited by 12 publications

References 14 publications

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Chemoselective O-acylation of hydroxyamino acids and amino alcohols under acidic reaction conditions: History, scope and applications

Chiral dirhodium catalysts derived from l-serine, l-threonine and l-cysteine: design, synthesis and application

Chiral Dirhodium Catalysts: A New Era for Asymmetric Catalysis

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