Recent Advances in Alkenyl sp² C–H and C–F Bond Functionalizations: Scope, Mechanism, and Applications

Chemical Reviews, Journal Year: 2022, Volume and Issue: 122(24), P. 17479 - 17646

Published: Oct. 14, 2022

Alkenes and their derivatives are featured widely in a variety of natural products, pharmaceuticals, advanced materials. Significant efforts have been made toward the development new practical methods to access this important class compounds by selectively activating alkenyl C(sp2)–H bonds recent years. In comprehensive review, we describe state-of-the-art strategies for direct functionalization sp2 C–H C–F until June 2022. Moreover, metal-free, photoredox, electrochemical also covered. For clarity, review has divided into two parts; first part focuses on currently available using different alkene as starting materials, second describes bond easily accessible gem-difluoroalkenes material. This includes scope, limitations, mechanistic studies, stereoselective control (using directing groups well metal-migration strategies), applications complex molecule synthesis where appropriate. Overall, aims document considerable advancements, current status, emerging work critically summarizing contributions researchers working fascinating area is expected stimulate novel, innovative, broadly applicable functionalizations coming

Language: Английский

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Recent advances in transition metal-free annulation toward heterocycle diversity based on the C–N bond cleavage of enaminone platform

Organic & Biomolecular Chemistry, Journal Year: 2022, Volume and Issue: 20(12), P. 2356 - 2369

Published: Jan. 1, 2022

Enaminones and analogous stable enamines are well known as platform building blocks in organic synthesis for the construction of heterocyclic compounds, especially N-heterocycles. To date, enaminones have been successfully employed various 5- or 6- membered heterocycles. Recently, synthetic protocols accomplished by diversity-oriented annulation reactions based on C-N bond cleavage gained notable success. In this review, development transition metal-free product featuring a is reviewed.

Language: Английский

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A Strategy for Accessing Trifluoromethyl Carbinol-Containing Chromones from o-Hydroxyaryl Enaminones and Trifluoroacetaldehyde/Ketone Derivatives

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(9), P. 5586 - 5596

Published: April 6, 2023

Herein, we present a practical strategy for the direct construction of structurally diverse trifluoromethyl carbinol-containing compounds, especially CF3-substituted tertiary alcohol with chromone derivatives from easily available o-hydroxyaryl enaminones and trifluoroacetaldehyde/ketone under metal-free conditions. This reaction features broad substrate scope good yields is scaled up. Notably, one-pot in two-steps obtained products amidines also developed to provide series multi-substituted pyrimidine bearing two unique hydroxyls one containing functional units.

Language: Английский

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The Domino Chromone Annulation and a Transient Halogenation-Mediated C–H Alkenylation toward 3-Vinyl Chromones

Organic Letters, Journal Year: 2020, Volume and Issue: 22(24), P. 9518 - 9523

Published: Dec. 3, 2020

Reported in this paper is a step economical method toward the general synthesis of 3-vinyl chromones via reactions between readily available o-hydroxyphenyl enaminones and various alkenes. The domino C–H alkenylation chromone annulation are involved, which enables products using both terminal internal alkenes key process transient halogenation.

Language: Английский

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Pd-Catalyzed Triple-Fold C(sp²)–H Activation with Enaminones and Alkenes for Pyrrole Synthesis via Hydrogen Evolution

Organic Letters, Journal Year: 2021, Volume and Issue: 23(11), P. 4363 - 4367

Published: May 20, 2021

The synthesis of NH-free pyrroles via Pd-catalyzed annulation enaminones and alkenes is reported. With the catalysis Pd(II), activation triple C(sp2)-H bonds, including one internal bond in enaminone, has been activated to provide various pyrroles. interesting evolution hydrogen gas from reactions observed by a detector.

Language: Английский

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Advances in the Transition Metal‐Free C—H Trifluoromethylation

Chinese Journal of Chemistry, Journal Year: 2022, Volume and Issue: 40(21), P. 2582 - 2594

Published: July 18, 2022

Comprehensive Summary Trifluoromethyl group is one of the most frequently available and promising functional groups in pharmaceutical, agrochemical as well material molecules. Developing synthetic methods for synthesis trifluoromethyl functionalized compounds by trifluoromethylation reactions occupies significant position modern organic chemistry. On other hand, a typical tool sustainable synthesis, transition metal‐free possesses unique advantages atom economy, easy product purification excellent eco‐tolerance. Consequently, constitute important approaches accessing trifluoromethylated Herein, advances C—H are reviewed first time. According to updated state‐of‐art, both catalytic conventional heating chemistry more photocatalysis included, covering C(sp 3 )–H bond, aromatic 2 bond non‐aromatic different substrates over last five years (2017—2021).

Language: Английский

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I₂-Promoted site-selective C–C bond cleavage of aryl methyl ketones as C1 synthons for constructing 5-acyl-1H-pyrazolo[3,4-b]pyridines

Organic Chemistry Frontiers, Journal Year: 2022, Volume and Issue: 9(16), P. 4416 - 4420

Published: Jan. 1, 2022

A novel iodine promoted [1 + 3 2] cleavage cyclization reaction for the synthesis of 1 H -pyrazolo[3,4- b ]pyridines from aryl methyl ketones, 5-aminopyrazoles and enaminones has been established.

Language: Английский

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Cascade in Situ Iodination, Chromone Annulation, and Cyanation for Site-Selective Synthesis of 2-Cyanochromones

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(6), P. 4017 - 4023

Published: March 2, 2023

A facile cascade reaction for the site selective synthesis of 2-cyanochromones is described. By using simple o-hydroxyphenyl enaminones and potassium ferrocyanide trihydrate (K4[Fe(CN)6]3·3H2O) as starting materials I2/AlCl3 promoters, products are furnished via tandem chromone ring formation C–H cyanation. The in situ 3-iodochromone a formal 1,2-hydrogen atom transfer (HAT) process account unconventional selectivity. In addition, 2-cyanoquinolin-4-one has been realized by employing corresponding 2-aminophenyl enaminone substrate.

Language: Английский

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Transition metal-free tunable synthesis of 3-(trifluoromethylthio) and 3-trifluoromethylsulfinyl chromones via domino C-H functionalization and chromone annulation of enaminones

Chinese Chemical Letters, Journal Year: 2024, Volume and Issue: 35(11), P. 109683 - 109683

Published: March 2, 2024

Language: Английский

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Silver‐catalyzed Cascade Bis‐heteroannulation Reaction of Enynones and o‐Hydroxyphenyl Enaminones: Access to Highly Functionalized 3‐Furylmethyl Chromones

Advanced Synthesis & Catalysis, Journal Year: 2024, Volume and Issue: 366(10), P. 2363 - 2369

Published: March 16, 2024

Abstract A synthetic protocol was developed to synthesize highly functionalized 3‐furylmethyl chromones from enynones and o ‐hydroxyphenyl enaminones via silver‐catalyzed cascade bis‐heteroannulation reaction. This strategy features broad substrate scope good functional group tolerance. Furthermore, the chromone skeleton shows potential application value through further gram‐scale synthesis derivatization.

Language: Английский

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