Palladium-Catalyzed Diastereoselective Oxyarylation of 2-Alkylindoles

Ramella, Vincenzo; He, Zhiheng; Daniliuc, Constantin G.; Studer, Armido

doi:10.1021/ol503689r

Cited by 27 publications

(8 citation statements)

References 35 publications

(14 reference statements)

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“…The mixture was stirred at room temperature for 5 min followed by the addition of CuI (0.0676 g, 0.3 mmol). After being stirred at room temperature for 12 h as monitored by TLC, the resulting suspension was filtered under vacuum, concentrated and purified by column chromatography on silica gel (petroleum ether/ethyl acetate=60/1) to afford 7b as an oil; yield: 5.4148 g (88%). 1 H NMR (400 MHz, CDCl 3 ): δ =7.25 (dd, J 1 =7.6 Hz, J 2 =1.2 Hz, 1 H, ArH), 7.10–7.04 (m, 1 H, ArH), 6.70–6.63 (m, 2 H, ArH), 4.16 (bs, 2 H, NH 2 ), 2.36 (d, J =6.4 Hz, 2 H, CH 2 ), 1.98–1.87 (m, 1 H, CH), 1.05 (d, J =6.8 Hz, 6 H, 2×CH 3 ); 13 C NMR (100 MHz, CDCl 3 ): δ =147.6, 132.0, 128.7, 117.8, 114.1, 109.0, 94.6, 77.8, 28.8, 28.2, 22.0; MS (%): m / z =173 (M + , 49.5), 130 (100); IR (neat): ν =3473, 3377, 3028, 1612, 1572, 1492, 1455, 1426, 1384, 1367, 1343, 1305, 1263, 1245, 1157 cm −1 .…”

Section: Methodsmentioning

confidence: 99%

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Miao

Zheng

et al. 2017

Adv Synth Catal

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Ab is(cycloocta-1,5-diene)nickel-catalyzed highly regio-and (E)-stereoselectivehydrocarboxylation of 2-alkynylanilines under very mild conditions has been developed to afford( E)-[2-(o-aminophenyl)]acrylic acids,w hich coulde asily be converted to (E)-3-alkylidene-2-indolinones with important potential bioactivity. Thes tereoselective syntheses of two biologically active molecules,( E)-3-benzylidene-2-indolinone( chemo-preventive potential in inducing NQO1 activity) and (E)-3-(3-methylbutylidene)-2-indolinone( an atural product isolated from Cimicifuga foetida with cytotoxic activity against HL-60 cells) are presented as examples.

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Section: Methodsmentioning

confidence: 99%

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Miao

Zheng

et al. 2017

Adv Synth Catal

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“…Of note, this interesting indene transformation was successfully also used in a total synthesis of a resveratrol-based natural product . For C2-substituted indoles or benzofurans, carboxylic acids can be added to trap intermediates of type B . The trapping with an acid can also be realized intramolecularly …”

Section: Oxidation Reactionsmentioning

confidence: 99%

Organic Synthesis Using Nitroxides

Leifert

Studer

2023

Chem. Rev.

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Nitroxides, also known as nitroxyl radicals, are long-lived or stable radicals with the general structure R 1 R 2 N−O • . The spin distribution over the nitroxide N and O atoms contributes to the thermodynamic stability of these radicals. The presence of bulky N-substituents R 1 and R 2 prevents nitroxide radical dimerization, ensuring their kinetic stability. Despite their reactivity toward various transient C radicals, some nitroxides can be easily stored under air at room temperature. Furthermore, nitroxides can be oxidized to oxoammonium salts (R 1 R 2 N�O + ) or reduced to anions (R 1 R 2 N−O − ), enabling them to act as valuable oxidants or reductants depending on their oxidation state. Therefore, they exhibit interesting reactivity across all three oxidation states. Due to these fascinating properties, nitroxides find extensive applications in diverse fields such as biochemistry, medicinal chemistry, materials science, and organic synthesis. This review focuses on the versatile applications of nitroxides in organic synthesis. For their use in other important fields, we will refer to several review articles. The introductory part provides a brief overview of the history of nitroxide chemistry. Subsequently, the key methods for preparing nitroxides are discussed, followed by an examination of their structural diversity and physical properties. The main portion of this review is dedicated to oxidation reactions, wherein parent nitroxides or their corresponding oxoammonium salts serve as active species. It will be demonstrated that various functional groups (such as alcohols, amines, enolates, and alkanes among others) can be efficiently oxidized. These oxidations can be carried out using nitroxides as catalysts in combination with various stoichiometric terminal oxidants. By reducing nitroxides to their corresponding anions, they become effective reducing reagents with intriguing applications in organic synthesis. Nitroxides possess the ability to selectively react with transient radicals, making them useful for terminating radical cascade reactions by forming alkoxyamines. Depending on their structure, alkoxyamines exhibit weak C−O bonds, allowing for the thermal generation of C radicals through reversible C−O bond cleavage. Such thermally generated C radicals can participate in various radical transformations, as discussed toward the end of this review. Furthermore, the application of this strategy in natural product synthesis will be presented.

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“…Recently, Itami et al reported synthesis of 2‐aryl‐3‐acyloxy‐2,3‐dihydrobenzofurans by treating benzofurans, arylboronic acids and carboxylic acids in the presence of Pd(OAc) 2 and 2,2,6,6‐tetramethylpiperidine oxide (TEMPO) (Scheme ) . In another effort, Studer group have described the Pd(OAc) 2 ‐catalyzed oxyarylation of N ‐protected 2‐alkylindoles by arylboronic acids and chloroacetic acid in the presence of TEMPO as a mild oxidant (Scheme ) . Both Itami and Studer reports include acyloxyarylation of electron‐rich alkenes.…”

Section: Introductionmentioning

confidence: 99%

Regio‐ and Diastereoselective KMnO₄/RCO₂H Mediated Acyloxyarylation of Chalcones – An Indirect α‐Arylation of Chalcones

et al. 2020

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Palladium-Catalyzed Diastereoselective Oxyarylation of 2-Alkylindoles

Cited by 27 publications

References 35 publications

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Organic Synthesis Using Nitroxides

Regio‐ and Diastereoselective KMnO₄/RCO₂H Mediated Acyloxyarylation of Chalcones – An Indirect α‐Arylation of Chalcones

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Palladium-Catalyzed Diastereoselective Oxyarylation of 2-Alkylindoles

Cited by 27 publications

References 35 publications

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Bis(cycloocta‐1,5‐diene)nickel‐Catalyzed Carbon Dioxide Fixation for the Stereoselective Synthesis of 3‐Alkylidene‐2‐indolinones

Organic Synthesis Using Nitroxides

Regio‐ and Diastereoselective KMnO4/RCO2H Mediated Acyloxyarylation of Chalcones – An Indirect α‐Arylation of Chalcones

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Regio‐ and Diastereoselective KMnO₄/RCO₂H Mediated Acyloxyarylation of Chalcones – An Indirect α‐Arylation of Chalcones