Ketone–Olefin Coupling of Aliphatic and Aromatic Carbonyls Catalyzed by Excited-State Acridine Radicals DOI

Nicholas J. Venditto,

Yiyang S. Liang,

Roukaya K. El Mokadem

et al.

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(26), P. 11888 - 11896

Published: June 23, 2022

Ketone–olefin coupling reactions are common methods for the formation of carbon–carbon bonds. This reaction class typically requires stoichiometric or super quantities metal reductants, and catalytic variations limited in application. Photoredox catalysis has offered an alternative method toward ketone–olefin reactions, although most scope to easily reducible aromatic carbonyl compounds. Herein, we describe a mild, metal-free using excited-state acridine radical reductant as photoredox catalyst. We demonstrate both intramolecular intermolecular couplings aliphatic ketones aldehydes. Mechanistic evidence is also presented supporting "olefin first" mechanism.

Language: Английский

Stereoselective amino alcohol synthesis via chemoselective electrocatalytic radical cross-couplings DOI

Jiawei Sun,

Shuanghu Wang, Kaid C. Harper

et al.

Nature Chemistry, Journal Year: 2025, Volume and Issue: unknown

Published: Jan. 3, 2025

Language: Английский

Citations

4
Cobalt-Catalyzed Intermolecular Hydrofunctionalization of Alkenes: Evidence for a Bimetallic Pathway DOI
Xiao‐Le Zhou, Fan Yang, Han‐Li Sun

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(18), P. 7250 - 7255

Published: April 23, 2019

A functional group tolerant cobalt-catalyzed method for the intermolecular hydrofunctionalization of alkenes with oxygen- and nitrogen-based nucleophiles is reported. This protocol features a strategic use hypervalent iodine(III) reagents that enables mechanistic shift from conventional cobalt–hydride catalysis. Key evidence was found supporting unique bimetallic-mediated rate-limiting step involving two distinct cobalt(III) species, which new carbon–heteroatom bond formed.

Language: Английский

Citations

127
Iron and cobalt catalysis: new perspectives in synthetic radical chemistry DOI
Sara H. Kyne, Guillaume Lefèvre, Cyril Ollivier

et al.

Chemical Society Reviews, Journal Year: 2020, Volume and Issue: 49(23), P. 8501 - 8542

Published: Jan. 1, 2020

Iron and cobalt complexes are at the origin of high valuable synthetic pathways involving radical intemediates.

Language: Английский

Citations

116
1,3‐Difunctionalizations of [1.1.1]Propellane via 1,2‐Metallate Rearrangements of Boronate Complexes DOI Creative Commons
Songjie Yu, Changcheng Jing, Adam Noble

et al.

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 59(10), P. 3917 - 3921

Published: Jan. 8, 2020

1,3-Disubstituted bicyclo[1.1.1]pentanes (BCPs) are valuable bioisosteres of para-substituted aromatic rings. The most direct route to these structures is via multicomponent ring-opening reactions [1.1.1]propellane. However, challenges associated with transformations mean that difunctionalized BCPs more commonly prepared by multistep reaction sequences BCP-halide intermediates. Herein, we report three- and four-component 1,3-difunctionalizations [1.1.1]propellane organometallic reagents, organoboronic esters, a variety electrophiles. This process achieved trapping intermediate BCP-metal species boronic esters form boronate complexes, which versatile intermediates whose electrophile-induced 1,2-metallate rearrangement chemistry enables broad range C-C bond-forming reactions.

Language: Английский

Citations

115
Catalytic Asymmetric Radical–Polar Crossover Hydroalkoxylation DOI
Christopher A. Discolo,

Eric E. Touney,

Sergey V. Pronin

et al.

Journal of the American Chemical Society, Journal Year: 2019, Volume and Issue: 141(44), P. 17527 - 17532

Published: Oct. 23, 2019

Asymmetric intramolecular hydrofunctionalization of tertiary allylic alcohols is described. This metal hydride-mediated catalytic radical–polar crossover reaction delivers corresponding epoxides in good to high enantioselectivity and constitutes the first example asymmetric hydrogen atom transfer-initiated process. A series modified cobalt salen complexes has proven optimal for achieving efficiency induction. Experimental data suggest that cationic may be involved enantiodetermining step, where cation−π interactions catalyst contribute

Language: Английский

Citations

114
Radical‐Based Synthesis and Modification of Amino Acids DOI Creative Commons
Francisco José Aguilar Troyano, Kay Merkens, Khadijah Anwar

et al.

Angewandte Chemie International Edition, Journal Year: 2020, Volume and Issue: 60(3), P. 1098 - 1115

Published: Aug. 26, 2020

Abstract Amino acids (AAs) are key structural motifs with widespread applications in organic synthesis, biochemistry, and material sciences. Recently, the development of milder more versatile radical‐based procedures, use strategies relying on radical chemistry for synthesis modification AAs has gained increased attention, as they allow rapid access to libraries novel unnatural containing a wide range motifs. In this Minireview, we provide broad overview advancements made field during last decade, focusing methods de novo α‐, β‐, γ‐AAs, well selective derivatisation canonical non‐canonical α‐AAs.

Language: Английский

Citations

114
1,2-Amino Alcohols via Cr/Photoredox Dual-Catalyzed Addition of α-Amino Carbanion Equivalents to Carbonyls DOI

J. Luca Schwarz,

Roman Kleinmans,

Tiffany O. Paulisch

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(5), P. 2168 - 2174

Published: Jan. 10, 2020

Herein, we report the synthesis of protected 1,2-amino alcohols starting from carbonyl compounds and α-silyl amines. The reaction is enabled by a Cr/photoredox dual catalytic system that allows in situ generation α-amino carbanion equivalents which act as nucleophiles. unique nature this was demonstrated through aminoalkylation ketones an acyl silane, classes electrophiles were previously unreactive toward addition alkyl-Cr reagents. Overall, broadens scope Cr-mediated alkylations discloses underexplored retrosynthetic strategy for alcohols.

Language: Английский

Citations

113
Catalyst- and Silane-Controlled Enantioselective Hydrofunctionalization of Alkenes by Cobalt-Catalyzed Hydrogen Atom Transfer and Radical-Polar Crossover DOI

Kousuke Ebisawa,

Kana Izumi,

Yuka Ooka

et al.

Journal of the American Chemical Society, Journal Year: 2020, Volume and Issue: 142(31), P. 13481 - 13490

Published: July 10, 2020

The catalytic enantioselective synthesis of tetrahydrofurans, which are found in the structures many biologically active natural products, via a transition-metal-catalyzed hydrogen atom transfer (TM-HAT) and radical-polar crossover (RPC) mechanism is described herein. Hydroalkoxylation nonconjugated alkenes proceeded efficiently with excellent enantioselectivity (up to 94% ee) using suitable chiral cobalt catalyst, N-fluoro-2,4,6-collidinium tetrafluoroborate, diethylsilane. Surprisingly, absolute configuration product was highly dependent on steric hindrance silane. Slow addition silane, dioxygen effect solvent, thermal dependence, DFT calculation results supported unprecedented scenario two competing selective mechanisms. For less-hindered diethylsilane, high concentration diffused carbon-centered radicals invoked diastereoenrichment an alkylcobalt(III) intermediate by radical chain reaction, eventually determined product. On other hand, more hindered silane resulted less opportunity for instead facilitating kinetic resolution during late-stage nucleophilic displacement alkylcobalt(IV) intermediate.

Language: Английский

Citations

106
Selected Topics in the Syntheses of Bicyclo[1.1.1]Pentane (BCP) Analogues DOI
Xiaoshen Ma, Luu N. Pham

Asian Journal of Organic Chemistry, Journal Year: 2019, Volume and Issue: 9(1), P. 8 - 22

Published: Oct. 24, 2019

Abstract This Minireview focuses on selected topics in the syntheses of bicyclo[1.1.1]pentane (BCP) analogues. A brief historical introduction was included. The content covers various synthetic routes 1‐substituted and 1,3‐disubstituted BCPs. Selective examples synthetically useful building blocks are summarized for each category organic chemists’ medicinal reference. compare‐and‐contrast analysis is also applied to evaluate these demonstrate progress strategic functional group transformations using modern methodologies. By systematically analyzing strategies access strained molecules, we hope that this will provide inspirations future developments area.

Language: Английский

Citations

103
Der “Persistent Radical Effect” in der organischen Chemie DOI
Dirk Leifert, Armido Studer

Angewandte Chemie, Journal Year: 2019, Volume and Issue: 132(1), P. 74 - 110

Published: May 22, 2019

Abstract Radikal‐Radikal‐Kupplungen sind nahezu diffusionskontrollierte Prozesse. Daher selektive Kreuzkupplungen zweier unterschiedlicher Radikale schwierig zu realisieren und stellen somit synthetisch nicht wertvolle Prozesse dar. Wenn die beiden allerdings eine unterschiedliche Lebensdauer aufweisen in gleichen Raten gebildet werden, wird Kreuzkupplung zum dominierenden Prozess. Die hohe Kreuzselektivität basiert auf einem kinetischen Phänomen, dem “Persistent Radical Effect” (PRE). In diesem Aufsatz von Simulationen einfacher Modellsysteme gestützte Erklärung des PRE geliefert. Weiter werden Stabilität Radikalen Bezug ihre verschiedene Beispiele für PRE‐vermittelte der Synthese diskutiert. Es gezeigt, dass Kupplungen persistenter mit transienten beschränkt ist. Der einhergehender hoher greift bereits, wenn ein Kupplungspartner langlebiger als das andere transiente Radikal Diese Tatsache erweitert signifikant Anwendungsgebiet PRE‐vermittelter Radikalchemie. Dieser ist zwei Teile aufgeteilt: 1) Kupplung oder organischer 2) Radikal‐Metall‐Kreuzungsreaktionen; hierbei Metall‐zentrierte Radikalspezies allgemeiner langlebige Übergangsmetallkomplexe, welche reagieren, diskutiert – Gebiet, jüngst stark expandiert

Citations

96