Rhodium-Catalyzed Diastereoselective C–H Activation/[4 + 2] Annulation of α,β-Unsaturated Amides with Bicyclic Alkenes

Organic Letters, Год журнала: 2024, Номер 26(2), С. 483 - 487

Опубликована: Янв. 10, 2024

Herein, we report a rare example of rhodium-catalyzed C–H activation/[4 + 2] annulation alkenyl amides with bicyclic alkenes under mild and green conditions. The reactivity the rhodium catalyst in this study differed from that observed cobalt-catalyzed activation/[3 between vinylic alkenes. In addition, reaction was performed EtOH at room temperature, which also displayed excellent diastereoselectivity, good functional group tolerance, air compatibility. A series novel bridged-ring skeletons were obtained to yields. Scale-up experiments carried out 1 or 0.75 mol % catalyst, affording desired skeleton

Язык: Английский

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Ligand‐Enabled [3+2] Annulation of Aromatic Acids with Maleimides by C(sp³)−H and C(sp²)−H Bond Activation

Chemistry - A European Journal, Год журнала: 2022, Номер 28(39)

Опубликована: Май 7, 2022

A palladium-catalyzed [3+2] annulation of substituted benzoic acids with maleimides leading to tricyclic heterocyclic molecules having a free carboxylic group in high atom- and step-economical manner is described. The reaction proceeds via dual C-H bond activation such as C(sp3 )-H at the benzylic position C(sp2 meta aromatics. An external ligand (MPAA) crucial for success present protocol. Further, decarboxylation esterification acid observed products were carried out.

Язык: Английский

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A Ruthenium-Catalyzed Cyclization to Dihydrobenzo[c]phenanthridinone from 7-Azabenzonorbornadienes with Aryl Amides

Organic Letters, Год журнала: 2022, Номер 24(29), С. 5260 - 5265

Опубликована: Июль 15, 2022

An efficient ruthenium(II)-catalyzed tandem C-C/C-N bond formation with aryl amides and 7-azabenzonorbornadienes has been developed to synthesize cis-fused dihydrobenzo[c]phenanthridinones. The amide group functions as a directing well leaving provides an easy access the pharmaceutically useful benzo[c]phenanthridine alkaloids such nitidine fagaronine analogues. present methodology is compatible various functional groups respect azabicyclic alkenes aromatic amides. reaction mechanism involving directing-group-assisted C-H activation was proposed supported by deuterium labeling studies.

Язык: Английский

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One-Pot Synthesis of Benzo[c]phenanthridine Alkaloids from 7-Azabenzonorbornadienes and Aryl Nitrones

Organic Letters, Год журнала: 2023, Номер 25(21), С. 3853 - 3858

Опубликована: Май 18, 2023

An efficient synthesis of benzo[c]phenanthridine alkaloids via a synergistic combination C-C bond formation and cycloaromatization reaction is described. Aryl nitrones react with 7-azabenzonorbornadienes in the presence Rh(III) catalyst, providing pharmaceutically useful derivatives good to moderate yields. Using this methodology, highly such as norfagaronine, norchelerythrine, decarine, norsanguinarine, nornitidine were prepared single step.

Язык: Английский

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A Short Total Synthesis of Benzophenanthridine Alkaloids via a Rhodium(III)-Catalyzed C–H Ring-Opening Reaction

The Journal of Organic Chemistry, Год журнала: 2021, Номер 86(21), С. 14826 - 14843

Опубликована: Сен. 28, 2021

The biologically important naturally available benzophenanthridines were prepared efficiently in three steps with overall good yields. A new synthetic methodology involving a rhodium(III) catalyzed redox-neutral ring-opening of 7-azabenzonorbornadienes aromatic aldoximes is developed to synthesize the target molecules. C–H reaction highly diastereoselective and compatible various sensitive functional group substituted as well 7-azabenzonorbornadienes. products transformed into 13,14-dehydrobenzo phenanthridine derivatives by HCl hydrolysis. Subsequently, 13,14-dehydrobenzophenanthridines converted benzophenanthridine alkaloids presence DDQ. possible mechanism was proposed for supported deuterium labeling studies.

Язык: Английский

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Metal‐Catalyzed Coupling of N‐Tosylhydrazones with Compounds Containing C‐H/Heteroatom‐H Bonds

Asian Journal of Organic Chemistry, Год журнала: 2024, Номер unknown

Опубликована: Авг. 16, 2024

Abstract The present review covers various advances in the field of metal‐catalyzed coupling N ‐tosylhydrazones with compounds containing C−H/heteroatom‐H bonds, including transition metal catalysts i. e., Pd, Rh, Cu, Ag, Ni and Co resulting alkylated, alkenylated, alkynylated, allenylated, annulated many other products. A carbene migratory insertion process play a key role carbon‐carbon single bond (C−C) double (C=C) formation undergoes variety cascade reactions to synthesize wide scope pharmaceutically medicinally valuable scaffoldings.

Язык: Английский

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Copper-Catalyzed Hydroamination of Oxa- and Azabenzonorbornadienes with Pyrazoles

The Journal of Organic Chemistry, Год журнала: 2021, Номер 87(1), С. 569 - 578

Опубликована: Дек. 24, 2021

An efficient and highly chemo- stereoselective copper-catalyzed hydroamination of oxa- azabenzonorbornadienes with various pyrazole derivatives is described. This catalytic process promoted by the presence N-heterocyclic carbene ligands KOt-Bu under mild simple reaction conditions, allows for direct synthesis new versatile functionalized oxa(aza)benzonorbornyl pyrazoles starting from readily available oxa(aza)bicyclic alkenes. The synthetic utility this method was demonstrated transformation obtained products into pyrazolyl-substituted naphthalenes.

Язык: Английский

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Benzocarbazole Synthesis via Visible-Light-Accelerated Rh(III)-Catalyzed C–H Annulation of Aromatic Amines with Bicyclic Alkenes

Organic Letters, Год журнала: 2021, Номер 23(20), С. 7740 - 7745

Опубликована: Окт. 1, 2021

A visible-light-accelerated Rh(III)-catalyzed C-H annulation of aromatic amines with bicyclic alkenes for the synthesis benzocarbazole derivatives was developed. In this approach, cooperation rhodium catalysis and visible-light irradiation, various reacted oxabicyclic azabicyclic smoothly at room temperature, delivering corresponding bridged oxa or aza tetrahydro benzocarbazoles in good to excellent yields. Moreover, a series benzo[b]carbazoles were synthesized conveniently through further aromatization one pot. The potential method demonstrated via directing-group removal, derivatization, scale-up reaction, fluorescence investigations.

Язык: Английский

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Cobalt-catalyzed highly diastereoselective [3 + 2] carboannulation reactions: facile access to substituted indane derivatives

Chemical Communications, Год журнала: 2021, Номер 58(9), С. 1386 - 1389

Опубликована: Дек. 20, 2021

Efficient oxidative [3 + 2] annulation reaction involving aryl hydrazones and heterobicyclic alkenes has been realized with inexpensive earth-abundant cobalt salts under aerobic conditions. The proceeds via directing-group-assisted C-H activation exo-selective migratory insertion, followed by the intramolecular nucleophilic attack of alkylcobalt(III) species onto imine high anti-diastereoselectivity to provide complex indane derivatives. generation three contiguous stereogenic centers within indanyl unit avoidance use stoichiometric amounts metal oxidants make this transformation more valuable appealing.

Язык: Английский

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Desymmetrization of Oxabenzonorbornadienes through Brønsted Acid‐Catalyzed Enantioselective (3+2) Cycloaddition with Hydrazones

Asian Journal of Organic Chemistry, Год журнала: 2023, Номер 12(7)

Опубликована: Июнь 16, 2023

Abstract This work presents the desymmetrization of oxabenzonorbornadienes through (3+2) cycloaddition reaction with hydrazones using a chiral Brønsted acid such as BINOL‐derived phosphoramide. catalyst appears most effective mediator for activation hydrazone via hydrazonium cation that reacts in fashion oxabenzonorbornadiene olefinic counterpart. Under optimized conditions, provided selectively exo products satisfactory yields and moderate stereoselectivities. The scope was explored displaying 21 examples these highly functionalized tetrahydroepoxybenzoindazole compounds. A mechanism is proposed to explain outcome reaction.

Язык: Английский

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