Enantioselective C3‐Allylation of Pyridines via Tandem Borane and Palladium Catalysis

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(34)

Published: July 3, 2023

Abstract Herein, we report a one‐pot method for enantioselective C−H allylation of pyridines at C3 via tandem borane and palladium catalysis. This involves borane‐catalyzed pyridine hydroboration to generate dihydropyridines, then palladium‐catalyzed the dihydropyridines with allylic esters, finally air oxidation allylated afford products. enables introduction an group excellent regio‐ enantioselectivities.

Language: Английский

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Oxidative Dearomatization of Pyridines

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(4), P. 2358 - 2363

Published: Jan. 17, 2024

Dearomatization of pyridines is a well-established synthetic approach to access piperidines. Although remarkably powerful, existing dearomatization processes have been limited the hydrogenation or addition carbon-based nucleophiles activated pyridiniums. Here, we show that arenophile-mediated dearomatizations can be applied directly introduce heteroatom functionalities without prior substrate activation. The arenophile platform in combination with olefin oxidation chemistry provides dihydropyridine cis-diols and epoxides. These previously elusive compounds are now readily accessible used for downstream preparation diversely functionalized

Language: Английский

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Pd-Catalysed asymmetric allylic alkylation of heterocycles: a user's guide

Chemical Society Reviews, Journal Year: 2024, Volume and Issue: 53(4), P. 1936 - 1983

Published: Jan. 1, 2024

This review analyses recent advances and strategies employed in the Pd-AAA of nucleophilic prochiral heterocycles. Each section is focused on a specific heterocycle, where optimisation data reaction scope have been carefully analysed.

Language: Английский

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Asymmetric Allylic Substitution Reactions Based on Relay Catalysis

Synthesis, Journal Year: 2024, Volume and Issue: 56(22), P. 3349 - 3364

Published: March 5, 2024

Abstract Transition-metal-catalyzed asymmetric allylic substitution reactions represent a hot research topic in the field of synthesis, with significant progress having been made. Among diverse catalysis systems, relay enables sequential activation multiple steps one pot and rapid construction chiral centers, providing simple powerful platform for organic synthesis. Recently, has successfully applied to reactions, variety challenging transformations have realized. This Short Review summarizes related on based over last decade. 1 Introduction 2 The General Transformation Model 3 Allylation Relays Further Reaction 4 Initial 5 Conclusion Outlook

Language: Английский

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Pd–NHC (NHC = N-Heterocyclic Carbene)-Catalyzed B-Alkyl Suzuki Cross-Coupling of 2-Pyridyl Ammonium Salts by N–C Activation: Application to the Discovery of Agrochemical Molecular Hybrids

Organic Letters, Journal Year: 2024, Volume and Issue: 26(11), P. 2309 - 2314

Published: March 11, 2024

2-Alkylpyridines are a privileged scaffold throughout the realm of organic synthesis and play key role in natural products, pharmaceuticals, agrochemicals. Herein, we report first B-alkyl Suzuki cross-coupling 2-pyridyl ammonium salts to access functionalized 2-alkylpyridines. The use well-defined, operationally simple Pd-NHCs permits for an exceptionally broad scope challenging C–N with organoboranes containing β-hydrogen, representing novel method discovery highly sought-after molecules plant protection.

Language: Английский

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Reversible hydrosilane addition to pyridines enabled by low-coordinate Ca(ii) and Yb(ii) hydrides

Inorganic Chemistry Frontiers, Journal Year: 2024, Volume and Issue: 11(14), P. 4336 - 4346

Published: Jan. 1, 2024

Low-coordinate dimeric Ca( ii ) and Yb( hydrides {[ t Bu 2 CarbAr ]MH(THF)} ]MH(η 6 -C 7 H 8 )} efficiently catalyze PhSiH 3 addition to pyridines at ambient T . At 90° C the same complex catalyzes reverse reaction.

Language: Английский

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Recent Advances in Sequentially Pd-Catalyzed One-Pot Syntheses of Heterocycles

Molecules, Journal Year: 2024, Volume and Issue: 29(22), P. 5265 - 5265

Published: Nov. 7, 2024

Sequential Pd-catalyzed one-pot synthetic methodologies have emerged as a powerful and versatile approach in organic synthesis, enabling the construction of complex heterocyclic architectures with high efficiency, selectivity, atom economy. This review discusses key advancements multistep, sequentially processes for accessing derivatives, focusing on classic reactions like Suzuki-Miyaura, Sonogashira, Heck, hydroamination extending to specialized techniques such directed C-H activation. The concatenation these steps has advanced scope strategies. A section is dedicated exploring cooperative use palladium other metals, particularly copper, ruthenium, gold, which broadened range accessible derivatives. Highlighted applications include synthesis biologically pharmaceutically relevant compounds, tris(hetero)aryl systems, spiro-oxindoles, indole These strategies not only streamline but also align green chemistry principles by minimizing purification reducing waste energy consumption. addresses current challenges limitations methodologies, offering insights into ongoing efforts optimize reaction conditions expand applicability sequential processes.

Language: Английский

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Reimagining Dearomatization: Arenophile-Mediated Single-Atom Insertions and π-Extensions

Accounts of Chemical Research, Journal Year: 2025, Volume and Issue: unknown

Published: March 11, 2025

ConspectusDearomatization of simple aromatics serves as one the most direct strategies for converting abundant chemical feedstocks into three-dimensional value-added products. Among such transformations, cycloadditions between arenes and alkenes have historically offered effective means to construct complex polycyclic architectures. However, traditionally harsh conditions, high-energy UV light irradiation, greatly limited scope this transformation. Nevertheless, recent progress has led development visible-light-promoted dearomative photocycloadditions with expanded capable preparing bicyclic structures.A fundamentally distinct approach involves visible-light activation arenophiles, which undergo para-photocycloaddition various aromatic compounds produce arene-arenophile cycloadducts. While only transiently stable subject retro-cycloaddition, further functionalization photocycloadducts allowed a wide collection dearomatization methodologies that access products orthogonal existing biological processes. Central strategy was observation photocycloaddition reveals π-system can be functionalized through traditional olefin chemistry. Coupled subsequent [4 + 2]-cycloreversion arenophile, process acts effectively isolate single from an ring. We developed several transformations bias methodology perform single-atom insertion π-extension reactions prepare unique cannot prepared easily means.Through application epoxidation, we were able develop method epoxidation pyridines arene-oxides pyridine-oxides, respectively. Notably, when arenophile chemistry is applied arenes, transposed site native olefinic reactivity, enabling site-selectivity functionalization. As result, oxygen (aza)arenes 3-benzoxepines. When applying in context cyclopropanations, accomplish cyclopropanation yield benzocycloheptatrienes upon cycloreversion. while Buchner ring expansion powerful carbon corresponding does not ring-expanded Furthermore, could utilized synthesis novel nanographenes M-region annulative (M-APEX) reaction. Traditionally, methods rely on reactivity at K- bay-region. arenophiles activate reactivity. arenophile-mediated diarylation, followed by cycloreversion, deliver π-extended exclusive selectivity.

Language: Английский

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The Construction of Highly Substituted Piperidines via Dearomative Functionalization Reaction

Angewandte Chemie International Edition, Journal Year: 2023, Volume and Issue: 62(49)

Published: Oct. 20, 2023

Nitrogen heterocycles play a vital role in pharmaceuticals and natural products, with the six-membered aromatic aliphatic architectures being commonly used. While synthetic methods for N-heterocycles are well-established, synthesis of their functionalized analogues, particularly piperidine derivatives, poses significant challenge. In that regard, we propose stepwise dearomative functionalization reaction construction highly decorated derivatives diverse functional handles. We also discuss challenges related to site-selectivity, regio- diastereoselectivity, provide insights into mechanism through mechanistic studies density theory computations.

Language: Английский

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Cobalt‐Catalyzed Bis‐Borylation of Quinolines: The Importance of the Cobalt Triplet State

Chemistry - A European Journal, Journal Year: 2023, Volume and Issue: 29(69)

Published: Oct. 10, 2023

We report herein a mild stereo- and regioselective dearomatization of quinolines using the simple low valent HCo(N2 )(PPh3 )3 complex that exhibits labile ligands. Conditions to form selectively, at room temperature, high-valued 1,4-bis-borylated tetrahydroquinolines from starting heteroaromatic compounds have been developed. The efficient selective functionalization large scope bearing various electron-donating or electron-withdrawing substituents is presented, as well post-modification resulting C-B bond. NMR labelling studies are consistent with cascade mechanism pathway, an in situ generated paramagnetic bis-quinoline cobalt(I) hydride complex. A first quinoline followed by cobalt(I)-catalyzed Markovnikov hydroboration remaining double bond allows introduction boronic ester group only C4 position. DFT calculations particularly highlight importance cobalt triplet state throughout reaction bring some rationalization for observed borylation.

Language: Английский

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