Palladium(II)-Catalyzed Cross-Coupling of Diazo Compounds and Isocyanides to Access Ketenimines

ACS Catalysis, Journal Year: 2020, Volume and Issue: 10(21), P. 12881 - 12887

Published: Oct. 20, 2020

Diazo compounds and isocyanides are reactive functionalities valuable building blocks commonly utilized in organic synthesis. Their cross-coupling for the synthesis of useful isolable ketenimines remains an unsolved challenge synthetic chemistry. Herein, we report a general method preparation via palladium-catalyzed easily accessible diazo with isocyanides. The reaction benefits from use readily available starting materials, wide substrate scope, high functional group tolerance, yield products, resultant amenable to further functionalization. Experimental findings DFT calculations unambiguously corroborate initial formation Pd(II)–isocyanide complex as active catalytic species, which enables migratory insertion Pd(II)–carbene into isocyanide, evidence suggesting that oxidation state Pd(II) unchanged during reaction.

Language: Английский

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Catalytic Asymmetric Chemodivergent C2 Alkylation and [3 + 2]-Cycloaddition of 3-Methylindoles with Aziridines

ACS Catalysis, Journal Year: 2018, Volume and Issue: 8(11), P. 10261 - 10266

Published: Oct. 3, 2018

Highly enantioselective C2 alkylation and inverse-electron-demand [3 + 2]-cycloaddition of 3-methylindoles with 2,2′-diester aziridine were accomplished. The chemodivergent synthesis provided an access to two kinds chiral indole derivatives in good yields stereoselectivities the presence N,N′-dioxide/Tm(OTf)3 or N,N′-dioxide/Ho(OTf)3 complexes. An eight-coordinated mode complex was confirmed by X-ray crystal diffraction interpret roles additives H2O 1,4-dioxane. In addition, control experiments indicated that substituent nitrogen atom determined conversion patterns divergent reactions.

Language: Английский

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Difluoroketenimine: Generation from Difluorocarbene and Isocyanide and Its [3 + 2] Cycloadditions with Alkenes or Alkynes

The Journal of Organic Chemistry, Journal Year: 2020, Volume and Issue: 85(15), P. 9791 - 9800

Published: July 7, 2020

Ketenimines have been explored as useful building blocks for the synthesis of heteroatom-containing cyclic compounds through cycloaddition with polar multiple bonds. Herein, we report difluoroketenimine nonpolar bonds, namely, alkenes or alkynes. The is generated from coupling tert-butyl isocyanide and difluorocarbene, which formed in situ (bromodifluoromethyl)trimethylsilane. then reacts alkynes to afford fluorinated pyrrolidines pyrroles. DFT study suggests that a (alkyl)(amino)carbene involved key intermediate these reactions.

Language: Английский

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Highly Chemo- and Diastereoselective Dearomative [3 + 2] Cycloaddition Reactions of Benzazoles with Donor–Acceptor Oxiranes

Organic Letters, Journal Year: 2018, Volume and Issue: 20(24), P. 8026 - 8029

Published: Dec. 11, 2018

A Sc(OTf)3-catalyzed dearomative [3 + 2] cycloaddition of benzazoles with donor-acceptor oxiranes through chemoselective C-C bond cleavage was developed under mild conditions. This reaction provides an efficient method to construct benzazolo[3,2- c]oxazole compounds in good yields and high diastereoselectivity. The has a general substrate scope, the electron-donating electron-withdrawing groups on aromatic ring afforded desired cycloadducts.

Language: Английский

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Synthesis of N-(Isoquinolin-1-yl)sulfonamides via Ag₂O-Catalyzed Tandem Reaction of ortho-Alkynylbenzaldoximes with Benchtop Stabilized Ketenimines

Organic Letters, Journal Year: 2021, Volume and Issue: 23(9), P. 3524 - 3529

Published: April 14, 2021

In this project, a moderately efficient approach to multisubstituted N-(isoquinolin-1-yl)sulfonamide derivatives was illustrated, utilizing ortho-alkynylbenzaldoximes and zwitterionic ketenimine salts in tandem reaction catalyzed by silver oxide. The oxophilicity of Ag2O, along with its nature as Lewis acid, pave the way for smooth [3 + 2] cycloaddition between isoquinoline N-oxides species, which is key step reaction. DFT calculation suggests that 1,3-dipolar nitrone proceeds through selective stepwise mechanism.

Language: Английский

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[3 + 3]-Cycloaddition of α-Diazocarbonyl Compounds and N-Tosylaziridines: Synthesis of Polysubstituted 2H-1,4-Oxazines through Synergetic Catalysis of AgOTf/Cu(OAc)₂

Organic Letters, Journal Year: 2019, Volume and Issue: 21(7), P. 2356 - 2359

Published: March 20, 2019

An impressive and new [3 + 3]-cycloaddition of α-diazocarbonyl compounds with N-tosylaziridines via synergetic catalysis AgOTf Cu(OAc)2 has been well described, which offers efficient access to highly substituted 2 H-1,4-oxazine derivatives. A variety were compatible substrates convenient operations under mild reaction conditions.

Language: Английский

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Synthesis of polycyclic spiroindolines via the cascade reaction of 3-(2-isocyanoethyl)indoles

Chemical Communications, Journal Year: 2021, Volume and Issue: 57(84), P. 11092 - 11095

Published: Jan. 1, 2021

Tandem reactions of the yttrium(iii) catalyzed ring-opening reaction 2,2'-diester aziridines with 3-(2-isocyanoethyl)indoles and subsequent Friedel-Crafts/Mannich/desulfonylation were reported. A series polycyclic spiroindolines containing tetrahydro-β-carbolines obtained in moderate to excellent yields (56-92%) one step under mild conditions. possible catalytic mechanism was also proposed.

Language: Английский

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Metal-free anomalous [5+1] cycloaddition reactions of donor–acceptor aziridines for the synthesis of 2H-1,4-oxazines

Chemical Communications, Journal Year: 2023, Volume and Issue: 59(55), P. 8572 - 8575

Published: Jan. 1, 2023

A new type of metal-free [5+1] cycloaddition reaction donor-acceptor aziridines with 2-(2-isocyanoethyl)indoles is reported herein. This method exhibits broad substrate scope and atom-economy. series 2H-1,4-oxazines containing an indole heterocycle skeleton were obtained in up to 92% yield under mild conditions. Control experiments revealed that free N-H crucial for the above transformations. The theoretical calculation studies provided guidance on in-depth insight into mechanism hydrogen-bond between carbonyl group was identified lower energy barrier transition states.

Language: Английский

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Highly Chemoselective Synthesis of Purino[3,2-c]oxazoles via the Asymmetric Dearomative [3+2] Cycloaddition of Purines with Donor–Acceptor Oxiranes

Organic Letters, Journal Year: 2022, Volume and Issue: 24(41), P. 7527 - 7532

Published: Oct. 7, 2022

A Ni(II)/bisoxazoline-catalyzed asymmetric dearomative [3+2] cycloaddition of substituted purines with donor–acceptor oxiranes was developed. This reaction, which proceeds via highly chemoselective C–C bond cleavage the oxiranes, accesses chiral purino[3,2-c]oxazole compounds (≤99% ee after enrichment crystallization). The electronic effects purine ring determine reactivity substrate. general applicability this method illustrated by gram-scale synthesis, diverse transformations product, and promising biological activities selected derivatives.

Language: Английский

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Diastereoselective synthesis of functionalized tetrahydro-γ-carbolines via a [3 + 3] cycloaddition of 2,2′-diester aziridines with β-(indol-2-yl)-α,β-unsaturated ketones

Chinese Chemical Letters, Journal Year: 2019, Volume and Issue: 31(5), P. 1293 - 1296

Published: Sept. 4, 2019

Language: Английский

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