Rhodium(III)‐Catalyzed Enantio‐ and Diastereoselective C−H Cyclopropylation of N‐Phenoxylsulfonamides: Combined Experimental and Computational Studies

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(7), P. 2890 - 2896

Published: Dec. 9, 2019

Cyclopropane rings are a prominent structural motif in biologically active molecules. Enantio- and diastereoselective construction of cyclopropanes through C-H activation arenes coupling with readily available cyclopropenes is highly appealing but remains challenge. A dual directing-group-assisted strategy was used to realize mild redox-neutral RhIII -catalyzed cyclopropylation N-phenoxylsulfonamides enantioselective, diastereoselective, regioselective fashion cyclopropenyl secondary alcohols as cyclopropylating reagent. Synthetic applications demonstrated highlight the potential developed method. Integrated experimental computational mechanistic studies revealed that reaction proceeds via RhV nitrenoid intermediate, Noyori-type outer sphere concerted proton-hydride transfer from alcohol Rh=N bond produces observed trans selectivity.

Language: Английский

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Recent Advances in Transition-Metal-Catalyzed C–H Alkylation with Three-Membered Rings

ACS Catalysis, Journal Year: 2022, Volume and Issue: 12(4), P. 2330 - 2347

Published: Feb. 1, 2022

Transition-metal-catalyzed alkylation of (hetero)arenes with three-membered carbo-/heterocycles involving C–H activation and ring scission has been greatly developed over the past few years. The chelation-assisted strategies for controlling reactivity site selectivity in these protocols include use nitrogen-containing directing groups, pre-existing functional a Catellani-type intermediate, thereby providing rapid access to numerous oxygen- or heterocyclic systems. This review gives an update area various catalytic methodologies applications total synthesis natural products rings as alkylating reagents, which are classified into following three categories on basis employed strategies: (i) directed by (ii) (iii) aryl-NBE intermediates (Catellani-type cascade reaction).

Language: Английский

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Recent Developments in Cyclopropane Cycloaddition Reactions

Trends in Chemistry, Journal Year: 2019, Volume and Issue: 1(8), P. 779 - 793

Published: July 19, 2019

Language: Английский

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Phosphine‐Catalyzed Activation of Alkylidenecyclopropanes: Rearrangement to Form Polysubstituted Furans and Dienones

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(31), P. 10698 - 10702

Published: May 15, 2019

We report a phosphine-catalyzed ring opening of electron-deficient alkylidenecyclopropanes (ACPs) to generate allylic phosphonium zwitterions that resemble the well-studied phosphine-allene adducts but exhibit distinct properties. The potent reactivity these intermediates has been demonstrated in three types substrate-controlled rearrangements alkylidenecyclopropylketones, which chemoselectively afford tri- and tetrasubstituted furans, trisubstituted dienones good yields.

Language: Английский

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Recent Achievements in the Rhodium‐Catalyzed Concise Construction of Medium N‐Heterocycles, Azepines and Azocines

Advanced Synthesis & Catalysis, Journal Year: 2020, Volume and Issue: 362(24), P. 5576 - 5600

Published: Nov. 13, 2020

Abstract Medium N‐heterocycles, azepines and azocines, serve as important skeletons that occurred widely in natural products, however, due to the lack of efficient synthetic methodologies, their application potential biologically active molecules, pharmaceuticals agrochemicals remained be explored. In this context, rhodium catalysis field featured good reactivity functional group tolerance, with readily available starting materials, enabled rapid access azocines. Delightfully, great achievements concise construction these 7 8‐membered N‐heterocycles under have been made, which mainly included cycloisomerization unsaturated C−X bonds (which might also combine ring‐opening strategy on strained rings), metal carbenoid or nitrene insertion involved transformations direct C−H activation reactions. Considering performance catalyst synthesis herein, we summarized recent results field, wish give further insight inspired more encouraging methodologies new drug discovery based N‐heterocycles. magnified image

Language: Английский

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The optical nonlinear properties of a new synthesized azo-nitrone compound

Optical Materials, Journal Year: 2021, Volume and Issue: 113, P. 110815 - 110815

Published: Jan. 22, 2021

Language: Английский

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Divergent Annulative C–C Coupling of Indoles Initiated by Manganese-Catalyzed C–H Activation

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(10), P. 9463 - 9470

Published: Aug. 31, 2018

Manganese(I)-catalyzed C–H activation of indoles and divergent annulative coupling with alkyne-tethered cyclohexadienones has been realized under operationally simple conditions. These annulation systems are condition control. The in the presence BPh3 additive followed a activation-alkyne insertion-Michael addition pathway, affording an exocyclic olefin attached to tetrahydrofuran ring. In contrast, when Zn(OAc)2/PivOH additives were introduced, initial olefination en route intramolecular Diels–Alder reaction subsequent elimination alcohol was deliver fused six-membered selectivity stands contrast those reported using rhodium(III) cobalt(III) catalysts, highlighting unique reactivity manganese catalysts.

Language: Английский

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Mn‐Catalyzed Dehydrocyanative Transannulation of Heteroarenes and Propargyl Carbonates through C−H Activation: Beyond the Permanent Directing Effects of Pyridines/Pyrimidines

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(15), P. 5090 - 5094

Published: Feb. 15, 2019

Abstract Pyridines/pyrimidines are common and effective directing groups in C−H activation. However, they poorly functionalizable heteroarenes. Reported this work is Mn‐catalyzed dehydrocyanative transannulation between three classes of heteroarenes propargyl carbonates. The pyridyl/pyrimidyl the initially function as to enable allenylation; then undergo intramolecular Diels–Alder/retro‐Diels–Alder reactions with allene moiety afford fused carbo/heterocycles. Three key intermediates at different stages reaction were isolated.

Language: Английский

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Cobalt-Catalyzed Annulation Reactions of Alkylidenecyclopropanes: Access to Spirocyclopropanes at Room Temperature

Organic Letters, Journal Year: 2019, Volume and Issue: 21(10), P. 3871 - 3875

Published: May 2, 2019

A bidentate chelation-assisted cobalt-catalyzed C(sp2)-H activation and annulation of benzamides alkylidenecyclopropanes (ACPs) has been realized. The unique reactivity organocobalt species led to selective migratory insertion across the more electron-rich C═C bond ACP followed by faster reductive elimination from seven-membered cobaltacycle leading spiro-dihydroisoquinoline derivatives with conservation cyclopropyl ring. operationally simple reaction conditions allowed C-H both aryl heteroaryl amides at room temperature.

Language: Английский

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Allylic Acetals as Acrolein Oxonium Precursors in Tandem C−H Allylation and [3+2] Dipolar Cycloaddition

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 58(28), P. 9470 - 9474

Published: May 9, 2019

Abstract The ruthenium(II)‐catalyzed C−H functionalization of (hetero)aryl azomethine imines with allylic acetals is described. initial formation allylidene(methyl)oxoniums from could trigger C(sp 2 )−H allylation, and subsequent endo ‐type [3+2] dipolar cycloaddition polar fragments to deliver valuable indenopyrazolopyrazolones. utility this method showcased by the late‐stage bioactive molecules such as estrone celecoxib. Combined experimental computational investigations elucidate a plausible mechanism new tandem reaction. Notably, reductive transformation synthesized compounds into biologically relevant diazocine frameworks highlights importance developed methodology.

Language: Английский

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