Palladium-Catalyzed Aerobic Oxidative Spirocyclization of Alkyl Amides with Maleimides via β-C(sp³)–H Activation

Organic Letters, Journal Year: 2023, Volume and Issue: 25(34), P. 6305 - 6310

Published: Aug. 22, 2023

An efficient method for the synthesis of bicyclic spirodiamine molecules via β-C(sp3)–H bond activation aliphatic amides, followed by cyclization with maleimides, has been developed. The reaction proceeds through an amide-directed alkyl amides and subsequent maleimides. methodology is highly compatible a wide variety Amides derived from biologically active fatty acids were also found to be protocol. A palladacycle was synthesized intermediate in this reaction. plausible mechanism proposed account spirocyclization.

Language: Английский

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Palladium-Catalysed Spiro-Cyclisation of Substituted Amino Acids with Maleimides via γ-C(sp³)–H Bond Activation

Organic Letters, Journal Year: 2025, Volume and Issue: unknown

Published: April 1, 2025

Achieving the site-selective functionalization of unactivated C(sp3)-H bonds remains a major challenge in organic synthesis. Herein, we report an efficient method for synthesis spiro pyrrolidine molecules via γ-C(sp3)-H bond activation substituted amino acids. A variety acid and alcohol derivatives, as well dipeptides, were functionalized using this method. Also, spirocyclization optically active substrates provided potential route preparing separable diastereomers pure enantiomeric form. Moreover, some mechanistic insights have been conducted to propose feasible reaction mechanism present reaction.

Language: Английский

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Multi-Component Syntheses of Spiro[furan-2,3′-indoline]-3-carboxylate Derivatives Using Ionic Liquid Catalysts

Molecules, Journal Year: 2024, Volume and Issue: 29(6), P. 1223 - 1223

Published: March 8, 2024

Two previously described Brønsted acidic ionic liquids, 3,3′-(1,6-hexanediyl)bis(1-methyl)-1H-imidazolium hydrogen sulfate (Cat1) and 1,1′-(1,6-hexanediyl)bis(pyridinium) (Cat2), were used as catalysts for the preparation of spiro[furan-2,3′-indoline]-3-carboxylate derivatives via a three-component reaction anilines, isatins (N-alkyl-indoline-2,3-diones), diethyl acetylenedicarboxylate, in high yields. The use ultrasonic (US) irradiation led to targeted products (1a–15a) yields ranging from 80% 98%. Under same conditions, sulfuric acid acetic Brønstedt catalyst did not yield desired benchmark product 1a.

Language: Английский

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NHC-Catalyzed Reaction of Aldehydes for C(sp2)–O Bond Formation

Catalysts, Journal Year: 2024, Volume and Issue: 14(4), P. 219 - 219

Published: March 22, 2024

In the past few decades, N-heterocyclic carbenes (NHCs) have opened new field of organocatalysis in synthetic organic chemistry. This review highlights dramatic progress NHC-catalyzed C–O bond formation based on activation aldehyde C(sp2)–H bonds. The oxidative and redox transformations for synthesis various molecules with structural diversity complexity are summarized. Furthermore, methods strategies NHC catalysis emerging continuously; thus, cooperative Brønsted acid, hydrogen-bonding catalyst, transition-metal photocatalyst also described.

Language: Английский

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Substrate-Controlled Regioselective Cascade Reactions of Deconjugated Butenolides and Cinnamaldehydes: Access to Structurally Diverse Spirobutenolides

Organic Letters, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 3, 2024

Two different cascade pathways to access spirobutenolides were achieved based on the substrate-controlled regioselectivity of deconjugated butenolides. A new class functional butenolides was designed and exhibited superior γ-regioselectivity in vinylogous Michael/Michael reactions with cinnamaldehydes. The aryl-substituted cinnamaldehydes underwent a Michael/Michael/aldol/dehydration process induced by double α-regioselectivities. Both conjugated could be obtained good yields excellent enantioselectivities.

Language: Английский

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Mechanisms and Origins of Stereoselectivity in NHC-Catalyzed Oxidative Reaction of Enals and Pyrroles: A Density Functional Theory Study

Physical Chemistry Chemical Physics, Journal Year: 2024, Volume and Issue: unknown

Published: Jan. 1, 2024

The mechanism, and chemo- stereoselectivity in the NHC-catalyzed oxidative reaction of enals pyrroles.

Language: Английский

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Five-membered ring systems: With more than 1 N atom

Progress in heterocyclic chemistry, Journal Year: 2024, Volume and Issue: unknown, P. 211 - 257

Published: Jan. 1, 2024

Language: Английский

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