Dimeric TADDOL Phosphoramidites in Asymmetric Catalysis: Domino Deracemization and Cyclopropanation of Sulfonium Ylides

Klimczyk, Sebastian; Misale, Antonio; Huang, Xueliang; Maulide, Nuno

doi:10.1002/anie.201503851

Cited by 77 publications

(42 citation statements)

References 55 publications

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“…Another example of asymmetric gold‐catalyzed [2+1] cycloaddition is the cyclopropanation of olefins with sulfonium ylides, which was reported by Maulide and co‐workers in 2015 . The optimal catalyst for this reaction was a novel type of bimetallic gold complex Au1 with a dimeric TADDOL‐derived phosphoramidite ligand, which exhibited better performance than its bidentate but mono‐auric sister Au2 and the monodentate mononuclear gold complex Au3 (Scheme ).…”

Section: Cycloaddition Reactionsmentioning

confidence: 99%

Gold‐Catalyzed Enantioselective Annulations

Zhang

2016

Chemistry A European J

221

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Non-oxidative,regioselective,and convergent access to densely functionalized oxazoles is realized in af unctional-group tolerant manner using alkynyl thioethers.S ulfur-terminated alkynes provideaccess to reactivity previously requiring strong donor-substituted alkynes such as ynamides.Sulfur does not act in an analogous donor fashion in this gold-catalyzed reaction, thus leading to complementary regioselective outcomes and addressing the limitations of using ynamides. Compared to other heteroatom-substituted alkynes,alkynyl thioethers are remarkably little explored in intermolecular late-transition-metal catalysis,d espite being readily accessed and robust. [1, 2] Ynamides,i nc ontrast, are privileged sub-strates:i np-acid catalysis their donor nature aids metal-alkyne coordination and affords highly polarized electro-philes,t hus providing the high chemo-and regioselectivity required for the discovery of efficient intermolecular reactions (Scheme 1a). [3,4] As the resulting inclusion of ad onor-nitrogen atom limits the utility of the products,r etaining the reactivity profile of these transformations whilst accessing more flexible and readily elaborated substitution patterns would be desirable.T he value of sulfur-substituted compounds [5] coupled with progress in C À Ca nd C-heteroatom bond formation from CÀSbonds, [6] renders alkynyl thioethers appealing alternatives to ynamides.I ndeed the ketenethio-nium pathway (Scheme 1a)f rom alkynyl thioethers has recently been invoked in proton-catalyzed reactions with nitriles [2g,h] and gold-catalyzed reactions with sulfides. [2i] Ynamides enabled the discovery of formal [3+ +2] dipolar cycloadditions with nucleophilic nitrenoids, [7] thus allowing intermolecular access to a-imino gold carbene-type reactivity for heterocycle synthesis (Scheme 1b). [8, 9] Such reactions, which do not depend on ynamides,a re scarce. [8b,h] As trong donor alkyne substituent proved critical in the formation of oxazoles using N-acyl pyridinium N-aminides,aselectron-rich alkynes such as anisole derivatives did not react (Scheme 1b, inset). [8a,b] Oxazoles are valuable synthetic intermediates [10,11] and structural components in bioactive natural products, [12] agrochemicals, [13] ligands, [14] and functional materials. [15] Despite recent advances,asingle modular and convergent route to trisubstituted oxazoles,which provides the structural and functional-group diversity needed across the 2-, 4-, and 5-positions,r emains unrealized. [16] Following our interest in the use of gold catalysis with sulfides [17] we report here on the reactivity of alkynyl thioethers with nucleophilic nitrenoids to prepare oxazoles. Importantly,t he regioselectivity is not consistent with ac on-trolling ketenethionium species.T he sulfur group plays an alternative role in enabling reactivity,t hus proving complementary to donor-enabled approaches. Ther eaction of the alkynyl thioether 1a and aminide 2a (Table 1) showed that conversion into the oxazole 3 was possible at 125 8 8Ci n1 ,2-dichlorobenzene (1,2-DCB;s ...

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Section: Cycloaddition Reactionsmentioning

confidence: 99%

Gold‐Catalyzed Enantioselective Annulations

Zhang

2016

Chemistry A European J

221

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“…Maulide, der in dieser Rubrik vorgestellt wurde, als er den Bayer Early Excellence in Science Award erhalten hatte,3a wurde 2013 Professor für organische Synthese an der Universität Wien. Seine Arbeit über eine diazo‐ und übergangsmetallfreie C‐H‐Insertion wurde auf dem Rücktitelbild von Chemistry—A European Journal präsentiert,3b und eine seiner neuesten Veröffentlichungen in der Angewandten Chemie behandelt die goldkatalysierte Deracemisierung von Allylestern 3c…”

Section: Ausgezeichnet …︁unclassified

The Chemical Record Lectureship: D. W. C. MacMillan / Heinrich‐Emanuel‐Merck‐Preis: P. S. Dittrich / EurJOC‐Nachwuchsforscherpreis: N. Maulide

2015

Angewandte Chemie

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“…Here, we report the successful realization of this concept and the development of ap ractical protocol for the atom-and step-economic synthesis of furo [3,4-d]tetrahydropyridazines in high yields and with excellent enantioselectivity( up to 96 % ee). [14] However,s everal established ligands, such as DIOP,t he Trost ligand,B INAP,J osiphos, DTBM-SEGPHOS,a nd phosphoramidites derived from 3,3'-disubstituted BINOLs, [15] only gave low enantioselectivities. We started our investigation by probingt he reaction of 2-(1alkynyl)-2-alken-1-one 3a [9b, 10] with azomethine imine 4a [13] in the presence of ac atalystg enerated in situ from Ph 3 PAuCl and AgOTf.…”

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confidence: 99%

“…95:5 in favor of the trans isomer (see the Supporting Information).E ncouraged by this result, we next focused on the asymmetric version of this reaction by employing chiral ligands. [14] However,s everal established ligands, such as DIOP,t he Trost ligand,B INAP,J osiphos, DTBM-SEGPHOS,a nd phosphoramidites derived from 3,3'-disubstituted BINOLs, [15] only gave low enantioselectivities. In the best case, the product 5a was obtainedw ith 34 % ee (41 %y ield) using ap hosphoramidite ligand (for details see the Supporting Information).…”

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confidence: 99%

Chiral Phosphine–Phosphite Ligands in Asymmetric Gold Catalysis: Highly Enantioselective Synthesis of Furo[3,4‐d]‐Tetrahydropyridazine Derivatives through [3+3]‐Cycloaddition

Neudörfl

Schmalz

2018

Chemistry A European J

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The Au -catalyzed reaction of 2-(1-alkynyl)-2-alken-1-ones with azomethine imines regio- and diastereoselectively affords furo[3,4-d]tetrahydropyridazines in a tandem cyclization/intermolecular [3+3]-cycloaddition process under mild conditions. By employing a chiral gold catalyst (prepared in situ from a Taddol-derived phosphine-phosphite ligand, Me SAuCl, and AgOTf) high yields and enantioselectivities (up to 94 % yield, up to 96 % ee) are obtained. The method provides an efficient modular route to substituted heterotricyclic furan derivatives and can be easily scaled up (using catalyst loads of only 0.15 mol %).

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Dimeric TADDOL Phosphoramidites in Asymmetric Catalysis: Domino Deracemization and Cyclopropanation of Sulfonium Ylides

Cited by 77 publications

References 55 publications

Gold‐Catalyzed Enantioselective Annulations

Gold‐Catalyzed Enantioselective Annulations

The Chemical Record Lectureship: D. W. C. MacMillan / Heinrich‐Emanuel‐Merck‐Preis: P. S. Dittrich / EurJOC‐Nachwuchsforscherpreis: N. Maulide

Chiral Phosphine–Phosphite Ligands in Asymmetric Gold Catalysis: Highly Enantioselective Synthesis of Furo[3,4‐d]‐Tetrahydropyridazine Derivatives through [3+3]‐Cycloaddition

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