Cobalt(III)-Catalyzed Regio- and Stereoselective α-Fluoroalkenylation of Arenes with gem-Difluorostyrenes

Organic Letters, Год журнала: 2016, Номер 18(24), С. 6320 - 6323

Опубликована: Дек. 5, 2016

A cobalt(III)-catalyzed α-fluoroalkenylation of different arenes with readily available gem-difluorostyrenes has been realized under mild and redox-neutral conditions. This reaction occurs via a C–H activation pathway offers step-economical access to various 1,2-diaryl-substituted monofluoroalkenes in excellent Z selectivity moderate yields.

Язык: Английский

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Mechanochemical Rhodium(III)-Catalyzed C–H Bond Amidation of Arenes with Dioxazolones under Solventless Conditions in a Ball Mill

ACS Catalysis, Год журнала: 2017, Номер 7(7), С. 4592 - 4596

Опубликована: Июнь 5, 2017

A procedure for the direct mechanochemical rhodium(III)-catalyzed C–H bond amidation of arenes with 1,4,2-dioxazol-5-ones as nitrogen source has been developed. The transformation proceeds under solventless conditions and does not require additional heating. corresponding ortho amidated products are formed in high yields shorter reaction times than solution.

Язык: Английский

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Cooperative Co(III)/Cu(II)-Catalyzed C–N/N–N Coupling of Imidates with Anthranils: Access to 1H-Indazoles via C–H Activation

Organic Letters, Год журнала: 2016, Номер 18(15), С. 3662 - 3665

Опубликована: Июль 14, 2016

Cooperative cobalt- and copper-catalyzed C–H activation of imidate esters oxidative coupling with anthranils allowed efficient synthesis 1H-indazoles in the absence metal oxidants. The anthranil acts as a convenient aminating reagent well an organic oxidant this transformation. copper catalyst likely functions at stage N–N formation.

Язык: Английский

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Recent Progress on Cyclic Nitrenoid Precursors in Transition‐Metal‐Catalyzed Nitrene‐Transfer Reactions

Chemistry - A European Journal, Год журнала: 2018, Номер 25(13), С. 3156 - 3180

Опубликована: Сен. 5, 2018

Abstract Nitrene‐transfer reactions are powerful synthetic tools for the direct incorporation of nitrogen atoms into organic molecules. The discovery novel nitrene‐transfer has been dominantly supported not only by improvements in transition‐metal catalysts but also employment precursors nitrenoids. Since pioneering work involving use azides and iminoiodinanes as practical nitrogen‐containing compounds was reported, a new approach using various N‐heterocycles containing strain energy or weak bond emerged. In this review, we briefly summarize history chemistry from viewpoint its precursors. particular, such 2 H ‐azirines, 1,4,2‐dioxazol‐5‐ones, 1,2,4‐oxadiazol‐5‐ones, isoxazol‐5(4 )‐ones, isoxazoles is comprehensively described, showing recent remarkable progress chemistry.

Язык: Английский

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Cobalt(III)- and Rhodium(III)-Catalyzed C–H Amidation and Synthesis of 4-Quinolones: C–H Activation Assisted by Weakly Coordinating and Functionalizable Enaminone

Organic Letters, Год журнала: 2017, Номер 19(7), С. 1812 - 1815

Опубликована: Март 30, 2017

Cobalt(III) and rhodium(III) catalysts exhibited complementary scope in C–H amidation of aryl enaminones. The reactions proceeded with broad under the assistance a weakly coordinating bifunctional enaminone directing group. electrophilicity group can be further utilized subsequent hydrolysis–cyclization to afford NH 4-quinolones telescoping reactions.

Язык: Английский

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Microwave-Assisted Cp*Co^III-Catalyzed C–H Activation/Double C–N Bond Formation Reactions to Thiadiazine 1-Oxides

Organic Letters, Год журнала: 2017, Номер 19(5), С. 1128 - 1131

Опубликована: Фев. 17, 2017

A microwave-assisted, Cp*CoIII-catalyzed direct C–H activation/double C–N bond formation reaction of simple NH-sulfoximines with 1,4,2-dioxazol-5-ones to produce diverse thiadiazine-1-oxides is reported. The tolerates a broad range functional groups under external oxidant-free conditions and only releases CO2 H2O as the sole byproducts. preliminary mechanistic studies revealed an electrophilic metalation pathway likely involved in reaction.

Язык: Английский

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Catalyst‐Controlled Regiodivergent Alkyne Insertion in the Context of C−H Activation and Diels–Alder Reactions: Synthesis of Fused and Bridged Cycles

Angewandte Chemie International Edition, Год журнала: 2017, Номер 56(28), С. 8163 - 8167

Опубликована: Май 17, 2017

Abstract Rhodium(III)‐ and cobalt(III)‐catalyzed C−H activation of indoles coupling with 1,6‐enynes is discussed. Under rhodium(III) catalysis, the alkyne insertion follows 2,1‐regioselectivity a subsequent type‐I intramolecular Diels–Alder reaction (IMDA) to afford [6,5]‐fused cycles. When catalyzed by cobalt(III) congener, 1,2‐insertion preferred, followed rare type‐II IMDA, thus leading bridged [3,3,1]‐cycles. This selectivity was mainly tuned steric sensitivity catalyst.

Язык: Английский

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Chelation-Assisted Rhodium-Catalyzed Direct Amidation with Amidobenziodoxolones: C(sp²)–H, C(sp³)–H, and Late-Stage Functionalizations

ACS Catalysis, Год журнала: 2016, Номер 6(9), С. 5930 - 5934

Опубликована: Авг. 3, 2016

Air-stable and convenient amidobenziodoxolones as an amidating reagent were disclosed to enable direct amidation on a wide range of C(sp2)–H bonds (hetero)arenes alkenes, well unactivated C(sp3)–H under RhIII catalysis. The approach access 49 examples structurally diverse amides is featured by mild conditions, complete chemoselectivity regioselectivity, broad substrate scope (not limited strongly heterocyclic coordinating groups), tolerance valuable functional substituents, such unprotected amine hydroxyl groups. synthetic applicability this protocol also demonstrated late-stage functionalization biologically important scaffolds.

Язык: Английский

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Cp*Co^III-Catalyzed Branch-Selective Hydroarylation of Alkynes via C–H Activation: Efficient Access to α-gem-Vinylindoles

ACS Catalysis, Год журнала: 2017, Номер 7(10), С. 7296 - 7304

Опубликована: Сен. 12, 2017

An efficient, atom-economical, and regioselective insertion of indoles into terminal alkynes has been realized via cobalt(III)-catalyzed C–H activation under mild conditions, leading to efficient synthesis α-gem-vinylindoles. The the follows a rare 1,2-selectivity, silyl alkynes, alkyl propargyl alcohols, protected amines are all applicable. mechanism this hydroarylation system studied in detail by combination experimental computational approaches. In reaction regioselectivity is dictated steric effects alkyne substituent, especially protonolysis stage. However, for amines, selectivity results from electronic during step, with being insignificant determination selectivity. internal also coupled high efficiency but low regioselectivity. Comparisons cobalt, rhodium, iridium catalysts have made terms reactivity, both cobalt catalysts.

Язык: Английский

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Co(III)-Catalyzed Enaminone-Directed C–H Amidation for Quinolone Synthesis

Organic Letters, Год журнала: 2017, Номер 19(9), С. 2418 - 2421

Опубликована: Апрель 20, 2017

We report herein the development of a Co(III)-catalyzed enaminone-directed C–H amidation method for synthetic access to quinolones, an important heterocyclic scaffold diverse pharmaceutically active structures. The coupling with dioxazolones and subsequent deacylation installed amide group allow consecutive C–N generation quinolones wide-ranging compatible substituent patterns.

Язык: Английский

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