C–H Activation: Toward Sustainability and Applications

ACS Central Science, Journal Year: 2021, Volume and Issue: 7(2), P. 245 - 261

Published: Feb. 2, 2021

Since the definition of "12 Principles Green Chemistry" more than 20 years ago, chemists have become increasingly mindful need to conserve natural resources and protect environment through judicious choice synthetic routes materials. The direct activation functionalization C–H bonds, bypassing intermediate functional group installation is, in abstracto, step atom economic, but numerous factors still hinder sustainability large-scale applications. In this Outlook, we highlight research areas seeking overcome challenges activation: pursuit abundant metal catalysts, avoidance static directing groups, replacement oxidants, introduction bioderived solvents. We close by examining progress made subfield aryl borylation from its origins, highly efficient precious Ir-based systems, emerging 3d catalysts. future growth field will depend on industrial uptake, thus urge researchers strive toward sustainable activation.

Language: Английский

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C–H activation

Nature Reviews Methods Primers, Journal Year: 2021, Volume and Issue: 1(1)

Published: June 17, 2021

Language: Английский

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Intermolecular [2π+2σ]-photocycloaddition enabled by triplet energy transfer

Nature, Journal Year: 2022, Volume and Issue: 605(7910), P. 477 - 482

Published: March 21, 2022

Language: Английский

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Photochemical intermolecular dearomative cycloaddition of bicyclic azaarenes with alkenes

Science, Journal Year: 2021, Volume and Issue: 371(6536), P. 1338 - 1345

Published: March 25, 2021

Heteroaromatics lured into cycloadditions The Diels-Alder reaction is widely used to produce six-membered carbon rings from alkenes and dienes. such as quinolines resemble dienes in principle, but practice their pairs of double bonds are inert toward because aromatic stabilization. Ma et al. report that by using an iridium photosensitizer, they could excite related azaarenes triplet states, thereby disrupting the aromaticity enabling intermolecular, Diels-Alder–like reactivity (see Perspective Schmidt). reactions proceeded exclusively at flanking carbons outside nitrogen-containing ring. Science , this issue p. 1338 ; see also 1313

Language: Английский

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Three-Component, Interrupted Radical Heck/Allylic Substitution Cascade Involving Unactivated Alkyl Bromides

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(22), P. 10173 - 10183

Published: May 7, 2020

Developing efficient and selective strategies to approach complex architectures containing (multi)stereogenic centers has been a long-standing synthetic challenge in both academia industry. Catalytic cascade reactions represent powerful means of rapidly leveraging molecular complexity from simple feedstocks. Unfortunately, carrying out Heck-type involving unactivated (tertiary) alkyl halides remains an unmet owing unavoidable β-hydride elimination. Herein, we show that modular, practical, general palladium-catalyzed, radical three-component coupling can indeed overcome the aforementioned limitations through interrupted Heck/allylic substitution sequence mediated by visible light. Selective 1,4-difunctionalization 1,3-dienes, such as butadiene, achieved employing different commercially available nitrogen-, oxygen-, sulfur-, or carbon-based nucleophiles bromides (>130 examples, mostly >95:5 E/Z, >20:1 rr). Sequential C(sp3)–C(sp3) C–X (N, O, S) bonds have constructed efficiently with broad scope high functional group tolerance. The flexibility versatility strategy illustrated gram-scale reaction streamlined syntheses ether, sulfone, tertiary amine products, some which would be difficult access via currently established methods.

Language: Английский

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Catalytic radical generation of π-allylpalladium complexes

Nature Catalysis, Journal Year: 2020, Volume and Issue: 3(4), P. 393 - 400

Published: March 23, 2020

Language: Английский

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Photosensitized Intermolecular Carboimination of Alkenes through the Persistent Radical Effect

Angewandte Chemie International Edition, Journal Year: 2019, Volume and Issue: 59(8), P. 3172 - 3177

Published: Dec. 3, 2019

Abstract An intermolecular, two‐component vicinal carboimination of alkenes has been accomplished by energy transfer catalysis. Oxime esters alkyl carboxylic acids were used as bifunctional reagents to generate both and iminyl radicals. Subsequently, addition the radical an alkene generates a transient for selective radical–radical cross‐coupling with persistent radical. Furthermore, this process provides direct access aliphatic primary amines α‐amino simple hydrolysis.

Language: Английский

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Metal-free photosensitized oxyimination of unactivated alkenes with bifunctional oxime carbonates

Nature Catalysis, Journal Year: 2021, Volume and Issue: 4(1), P. 54 - 61

Published: Jan. 4, 2021

Language: Английский

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Machine Learning for Chemical Reactivity: The Importance of Failed Experiments

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(29)

Published: May 5, 2022

Abstract Assessing the outcomes of chemical reactions in a quantitative fashion has been cornerstone across all synthetic disciplines. Classically approached through empirical optimization, data‐driven modelling bears an enormous potential to streamline this process. However, such predictive models require significant quantities high‐quality data, availability which is limited: Main reasons for include experimental errors and, importantly, human biases regarding experiment selection and result reporting. In series case studies, we investigate impact these drawing general conclusions from reaction revealing utmost importance “negative” examples. Eventually, studies into data expansion approaches showcase directions circumvent limitations—and demonstrate perspectives towards long‐term quality enhancement chemistry.

Language: Английский

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Predicting Reaction Yields via Supervised Learning

Accounts of Chemical Research, Journal Year: 2021, Volume and Issue: 54(8), P. 1856 - 1865

Published: March 31, 2021

ConspectusNumerous disciplines, such as image recognition and language translation, have been revolutionized by using machine learning (ML) to leverage big data. In organic synthesis, providing accurate chemical reactivity predictions with supervised ML could assist chemists reaction prediction, optimization, mechanistic interrogation.To apply reactions, one needs define the object of prediction (e.g., yield, enantioselectivity, solubility, or a recommendation) represent reactions descriptive Our group's effort has focused on representing DFT-derived physical features reacting molecules conditions, which serve for building models.In this Account, we present review perspective three studies conducted our group where models employed predict yield. First, focus small data set 16 phosphine ligands were evaluated in single Ni-catalyzed Suzuki–Miyaura cross-coupling reaction, yield was modeled linear regression. setting, regression complexity is strongly limited amount available data, emphasize importance identifying that are directly relevant reactivity. Next, trained two larger sets obtained high-throughput experimentation (HTE). With hundreds thousands available, more complex can be explored, example, algorithmically perform feature selection from broad candidate features. We examine how variety algorithms model these well generalize out-of-sample substrates. Specifically, compare use DFT-based featurization baseline carry no information, is, random features, naive non-ML averages yields share same conditions substrate combinations. find only sets, leads significant, although moderate, improvement. The source improvement further isolated specific allowed us formulate testable hypothesis validated experimentally. Finally, offer remarks HTE focusing algorithmic improvements training.Statistical methods chemistry rich history, but recently gained widespread attention development. As untapped potential novel tools likely arise future research. suggest lead improved over simpler modeling facilitate understanding dynamics. However, research development required establish an indispensable tool modeling.

Language: Английский

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