Ligand-Controlled Orthogonal Selectivity between δ and γ Positions of Long-Chain Picolinamides DOI

Soumya Kumar Sinha,

Nupur Goswami, Yingzi Li

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(16), P. 12681 - 12693

Published: Aug. 8, 2024

Aliphatic C(sp3)–H bonds are inherently difficult to activate, owing their inertness and chemical indistinguishability. This challenge has been overcome mostly by a directing group approach; however, the regioselectivity in distal aliphatic positions substrate-dependent, with substrate bias being prerequisite for activation, direct consequence of Thorpe–Ingold effect. Extending methodology straight-chain substrates, which all available compatible toward functionalization, long-standing problem. To this aim, we attempted develop ligand-enabled orthogonal selectivity between δ γ long-chain picolinamides regioselective fashion. These alkyl amines, assistance picolinic acid group, can be orthogonally functionalized just changing ligand, other reaction parameters remaining constant, signifying immense importance ligand controlling aforementioned such inert bonds. Experimental as well DFT studies have carried out generalize nature that would successful promoting these positions, electron-rich pyridone ligands favoring selective functionalization while electron-deficient tuning favorably position. tuned from also mechanistically established through control reactions, kinetic studies, theoretical calculations.

Language: Английский

Metallaphotoredox catalysis for sp3C–H functionalizations through hydrogen atom transfer (HAT) DOI
Jingchang Zhang, Magnus Rueping

Chemical Society Reviews, Journal Year: 2023, Volume and Issue: 52(12), P. 4099 - 4120

Published: Jan. 1, 2023

sp 3 C–H functionalizations under the combination of photocatalytic HAT and transition metal catalysis.

Language: Английский

Citations

98
Radical Polarity DOI
Jacob J. A. Garwood, Andrew D. Chen, David A. Nagib

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: unknown

Published: Oct. 3, 2024

The polarity of a radical intermediate profoundly impacts its reactivity and selectivity. To quantify this influence predict effects, the electrophilicity/nucleophilicity >500 radicals has been calculated. This database open-shell species entails frequently encountered synthetic intermediates, including centered at sp

Language: Английский

Citations

45
Enhanced Excited-State Hydricity of Pd–H Allows for Unusual Head-to-Tail Hydroalkenylation of Alkenes DOI
Sumon Sarkar, Soumen Ghosh, Daria Kurandina

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(22), P. 12224 - 12232

Published: May 24, 2023

Photoinduced enhancement of hydricity palladium hydride species enables unprecedented addition-like (“hydridic”) hydropalladation electron-deficient alkenes, which allows for chemoselective head-to-tail cross-hydroalkenylation and electron-rich alkenes. This mild general protocol works with a wide range densely functionalized complex Notably, this approach also highly challenging cross-dimerization electronically diverse vinyl arenes heteroarenes.

Language: Английский

Citations

31
Cooperative Fe/Co-Catalyzed Remote Desaturation for the Synthesis of Unsaturated Amide Derivatives DOI
Yanjun Wan, Emmanuel Ramírez,

Ayzia Ford

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4985 - 4992

Published: Feb. 6, 2024

Unsaturated amides represent common functional groups found in natural products and bioactive molecules serve as versatile synthetic building blocks. Here, we report an iron(II)/cobalt(II) dual catalytic system for the syntheses of distally unsaturated amide derivatives. The transformation proceeds through iron nitrenoid-mediated 1,5-hydrogen atom transfer (1,5-HAT) mechanism. Subsequently, radical intermediate undergoes hydrogen abstraction from vicinal methylene by a cobaloxime catalyst, efficiently yielding β,γ- or γ,δ-unsaturated derivatives under mild conditions. efficiency Co-mediated HAT can be tuned varying different auxiliaries, highlighting generality this protocol. Remarkably, desaturation protocol is also amenable to practical scalability, enabling synthesis carbamates ureas, which readily converted into various valuable molecules.

Language: Английский

Citations

7
Synthesis of non-canonical amino acids through dehydrogenative tailoring DOI
Xin Gu,

Yu‐An Zhang,

Shuo Zhang

et al.

Nature, Journal Year: 2024, Volume and Issue: 634(8033), P. 352 - 358

Published: Aug. 29, 2024

Language: Английский

Citations

7
Directed Photochemically Mediated Nickel-Catalyzed (Hetero)arylation of Aliphatic C–H Bonds DOI

R. Thomas Simons,

Meganathan Nandakumar, Kitae Kwon

et al.

Journal of the American Chemical Society, Journal Year: 2023, Volume and Issue: 145(7), P. 3882 - 3890

Published: Feb. 13, 2023

Site-selective functionalization of unactivated C(sp3)–H centers is challenging because the ubiquity and strength alkyl C–H bonds. Herein, we disclose a position-selective C(sp3)–C(sp2) cross-coupling reaction. This process engages bonds aryl bromides, utilizing catalytic quantities photoredox-capable molecule nickel precatalyst. Using this technology, selective arises owing to 1,6-hydrogen atom transfer (HAT) that guided by pendant alcohol-anchored sulfamate ester. These transformations proceed directly from N–H bonds, in contrast previous directed, radical-mediated, arylation processes, which have relied on prior oxidation reactive nitrogen center reactions with nucleophilic arenes. Moreover, these conditions promote at secondary good yields excellent selectivity.

Language: Английский

Citations

14
Oxidations of Alcohols, Aldehydes, and Diols Using NaBr and Selectfluor DOI
Harshit Joshi, Debobrata Paul, Shyam Sathyamoorthi

et al.

The Journal of Organic Chemistry, Journal Year: 2023, Volume and Issue: 88(15), P. 11240 - 11252

Published: July 25, 2023

We present protocols for the oxidation of alcohols and aldehydes oxidative cyclization diols which use a combination Selectfluor NaBr. For most substrates, optimal solvent system is 1:1 mixture CH3CN/H2O, but, in select cases, biphasic mixtures EtOAc/H2O or CH2Cl2/H2O are superior. This procedure operationally simple, uses inexpensive readily available reagents, tolerates variety functional groups. Mechanistic studies suggest that active oxidant hypobromous acid, generated by almost instantaneous Br– an aqueous milieu.

Language: Английский

Citations

10
Nitrogenation and Oxygenation of an Unstrained C–C Bond Enabled by the Merger of Visible-Light and Cu-Catalysis DOI
Yu Wang, Huan Meng, Sifan Li

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(4), P. 2402 - 2408

Published: Jan. 31, 2024

Unstrained carbon–carbon bonds are among the most prevalent and inert chemical bonds. Thus, developing synthetic transformations directly from unstrained under mild conditions is ideal yet challenging due to inertness steric hindrance. Here, a visible-light copper-catalyzed azidation etherification of remote C–C bond amines via 1,4-aryl migration have been reported. This redox-neutral protocol shows exquisite site-selectivity, broad scope, good functional group tolerance, transforming C–N C–O at room temperature. Facile derivatizations benzyl azide products into free amines, triazoles, phosphamides highlight potential utility this method for target molecule synthesis medicinal chemistry.

Language: Английский

Citations

4
γ-Amino C(sp3)–H Functionalization of Aliphatic Amines through a Light-Driven Triple Catalysis DOI

Masanari Nakagawa,

Kazunori Nagao, Hirohisa Ohmiya

et al.

ACS Catalysis, Journal Year: 2024, Volume and Issue: 14(10), P. 8005 - 8012

Published: May 9, 2024

We report intra- and intermolecular γ-amino C(sp3)–H functionalization of aliphatic amines using a vinylsulfone-based HAT (hydrogen atom transfer) auxiliary triple catalysis, which is composed photoredox, cobalt, Brønsted acid catalysts under visible light irradiation. The process accomplishes four elementary steps: (i) electrophilic carbon-centered radical formation on the via MHAT (metal hydride hydrogen reaction, (ii) generation through 1,6-HAT (iii) single-electron oxidation to carbocation equivalents, (iv) nucleophilic substitution with internal or external nucleophiles. As result, this afforded γ-amino-functionalized products, such as azetidines, 1,3-diamine, 1,3-aminoalcohol derivatives.

Language: Английский

Citations

4
Hydrogen Atom Transfer (HAT)-Mediated Remote Desaturation Enabled by Fe/Cr–H Cooperative Catalysis DOI
Yanjun Wan,

Augustine K. Adda,

Jin Qian

et al.

Journal of the American Chemical Society, Journal Year: 2024, Volume and Issue: 146(7), P. 4795 - 4802

Published: Feb. 8, 2024

An iron/chromium system (Fe(OAc)2, CpCr(CO)3H) catalyzes the preparation of β,γ- or γ,δ-unsaturated amides from 1,4,2-dioxazol-5-ones. acyl nitrenoid iron complex seems likely to be responsible for C–H activation. A cascade three H• transfer steps appears involved: (i) abstraction a remote bond by N, (ii) Cr and (iii) radical substituent Cr•. The observed kinetic isotope effects are consistent with proposed mechanism if formation is rate-determining step. Fe/Cr catalysts can also desaturate substituted 1,4,2-dioxazol-5-ones 3,5-dienamides.

Language: Английский

Citations

3