scholarly journals Cu(OTf)2-Mediated Ionizing Cross-Coupling of N(sp) and N(sp2) with Arylboronic Acids

2020 ◽  
Author(s):  
Allan Watson ◽  
Nicola Bell ◽  
Chao Xu ◽  
James Fyfe ◽  
Julien Vantourout ◽  
...  
Keyword(s):  
Late Stage ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Subsequent Generation ◽  
Mechanistic Studies ◽  
Arylboronic Acids ◽  
Bond Forming ◽  
Drug Synthesis ◽  
C And N ◽  
Metal Catalyzed

Metal-catalyzed C–N cross-coupling generally forms C–N bonds by reductive elimination from metal complexes bearing covalent C- and N-ligands. We have identified a Cu-mediated C–N cross-coupling that uses a dative N-ligand in the bond forming event, which, in contrast to conventional methods, generates reactive cationic products. Mechanistic studies suggest the process operates via transmetalation of an aryl organoboron to a Cu(II) complex bearing neutral N-ligands, such as nitriles or N-heterocycles. Subsequent generation of a putative Cu(III) complex enables the oxidative C–N coupling to take place, delivering nitrilium intermediates and pyridinium products. The reaction is general for a range of N(sp) and N(sp<sup>2</sup>) precursors and can be applied to drug synthesis and late-stage N-arylation, and the limitations in the methodology are mechanistically evidenced.

scholarly journals Cu(OTf)2-Mediated Ionizing Cross-Coupling of N(sp) and N(sp2) with Arylboronic Acids

2020 ◽  
Author(s):  
Allan Watson ◽  
Nicola Bell ◽  
Chao Xu ◽  
James Fyfe ◽  
Julien Vantourout ◽  
...  
Keyword(s):  
Late Stage ◽  
Cross Coupling ◽  
Reductive Elimination ◽  
Subsequent Generation ◽  
Mechanistic Studies ◽  
Arylboronic Acids ◽  
Bond Forming ◽  
Drug Synthesis ◽  
C And N ◽  
Metal Catalyzed

Metal-catalyzed C–N cross-coupling generally forms C–N bonds by reductive elimination from metal complexes bearing covalent C- and N-ligands. We have identified a Cu-mediated C–N cross-coupling that uses a dative N-ligand in the bond forming event, which, in contrast to conventional methods, generates reactive cationic products. Mechanistic studies suggest the process operates via transmetalation of an aryl organoboron to a Cu(II) complex bearing neutral N-ligands, such as nitriles or N-heterocycles. Subsequent generation of a putative Cu(III) complex enables the oxidative C–N coupling to take place, delivering nitrilium intermediates and pyridinium products. The reaction is general for a range of N(sp) and N(sp<sup>2</sup>) precursors and can be applied to drug synthesis and late-stage N-arylation, and the limitations in the methodology are mechanistically evidenced.

scholarly journals Heterobiaryl synthesis by contractive C–C coupling via P(V) intermediates

Science ◽  
2018 ◽  
Vol 362 (6416) ◽  
pp. 799-804 ◽  
Author(s):  
Michael C. Hilton ◽  
Xuan Zhang ◽  
Benjamin T. Boyle ◽  
Juan V. Alegre-Requena ◽  
Robert S. Paton ◽  
...  
Keyword(s):  
Cross Coupling ◽  
The Other ◽  
Coupling Reactions ◽  
Mechanistic Studies ◽  
Alternative Approach ◽  
Metal Catalyzed ◽  
Polar Functional Groups ◽  
Pharmacological Function ◽  
Complex Drug ◽  
Acidic Alcohol

Heterobiaryls composed of pyridine and diazine rings are key components of pharmaceuticals and are often central to pharmacological function. We present an alternative approach to metal-catalyzed cross-coupling to make heterobiaryls using contractive phosphorus C–C couplings, also termed phosphorus ligand coupling reactions. The process starts by regioselective phosphorus substitution of the C–H bonds para to nitrogen in two successive heterocycles; ligand coupling is then triggered via acidic alcohol solutions to form the heterobiaryl bond. Mechanistic studies imply that ligand coupling is an asynchronous process involving migration of one heterocycle to the ipso position of the other around a central pentacoordinate P(V) atom. The strategy can be applied to complex drug-like molecules containing multiple reactive sites and polar functional groups, and also enables convergent coupling of drug fragments and late-stage heteroarylation of pharmaceuticals.

scholarly journals Modular synthesis of α-fluorinated arylmethanes via desulfonylative cross-coupling

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Masakazu Nambo ◽  
Jacky C.-H. Yim ◽  
Luiza B. O. Freitas ◽  
Yasuyo Tahara ◽  
Zachary T. Ariki ◽  
...  
Keyword(s):  
Biological Activity ◽  
Late Stage ◽  
Recent Progress ◽  
Cross Coupling ◽  
Biologically Active Compounds ◽  
Biologically Active ◽  
Active Compounds ◽  
Arylboronic Acids ◽  
Modular Synthesis ◽  
Synthetic Routes

Abstract α-Fluoromethylarenes are common substructures in pharmaceuticals and agrochemicals, with the introduction of fluorine often resulting in improved biological activity and stability. Despite recent progress, synthetic routes to α-fluorinated diarylmethanes are still rare. Herein we describe the Pd-catalyzed Suzuki-Miyaura cross-coupling of α-fluorinated benzylic triflones with arylboronic acids affording structurally diverse α-fluorinated diarylmethanes. The ease of synthesis of fluorinated triflones as the key starting materials enables powerful late-stage transformations of known biologically active compounds into fluorinated analogs.

Catalytic enantioselective transformations of borylated substrates: Preparation and synthetic applications of chiral alkylboronates

2012 ◽  
Vol 84 (11) ◽  
pp. 2263-2277 ◽  
Author(s):  
Dennis G. Hall ◽  
Jack C. H. Lee ◽  
Jinyue Ding
Keyword(s):  
Transition Metal ◽  
Late Stage ◽  
Palladium Catalysis ◽  
Cross Coupling ◽  
Conjugate Additions ◽  
The Past ◽  
Allylic Substitutions ◽  
Recent Approach ◽  
Organic Functional Groups ◽  
Metal Catalyzed

Organoboronic acid derivatives are well-established intermediates for the preparation of alcohols and amines, and in the formation of C–C bonds via different reactions, including homologations, carbonyl allylboration, or transition-metal-catalyzed cross-coupling chemistry. In the past decade, there has been great interest in the development of catalytic enantioselective methods for the preparation of chiral, optically enriched organoboronates as precursors of enantioenriched compounds. While the mainstream strategy remains the late-stage borylation of organic functional groups, our group has focused on an alternate strategy focused on modification of boron-containing substrates. In this way, acyclic and cyclic secondary alkyl- and allyl-boronates were prepared through catalytic enantioselective processes such as [4 + 2] cycloadditions, isomerizations, allylic substitutions, and conjugate additions. The resulting optically enriched boronates have been successfully utilized in the syntheses of complex natural products and drugs. One remaining challenge in the chemistry of secondary alkylboronate derivatives is their cross-coupling, especially with control of stereoselectivity. In this regard, our recent approach featured the conjugate asymmetric borylation of β-boronyl acrylates, providing the first enantioselective preparation of highly optically enriched 1,1-diboronyl derivatives. The chirality of these geminal diboron compounds is conferred through the use of two distinct boronate adducts, which can be coupled chemo- and stereoselectively with a variety of aryl and alkenyl halides under palladium catalysis.

scholarly journals Asymmetric benzylic C(sp3)−H acylation via dual nickel and photoredox catalysis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Leitao Huan ◽  
Xiaomin Shu ◽  
Weisai Zu ◽  
De Zhong ◽  
Haohua Huo
Keyword(s):  
Carboxylic Acids ◽  
Organic Synthesis ◽  
Late Stage ◽  
Coupling Reaction ◽  
Cross Coupling ◽  
Photoredox Catalysis ◽  
Mechanistic Studies ◽  
Cross Coupling Reaction ◽  
Aryl Ketones ◽  
Alkyl Benzenes

AbstractAsymmetric C(sp3)−H functionalization is a persistent challenge in organic synthesis. Here, we report an asymmetric benzylic C−H acylation of alkylarenes employing carboxylic acids as acyl surrogates for the synthesis of α-aryl ketones via nickel and photoredox dual catalysis. This mild yet straightforward protocol transforms a diverse array of feedstock carboxylic acids and simple alkyl benzenes into highly valuable α-aryl ketones with high enantioselectivities. The utility of this method is showcased in the gram-scale synthesis and late-stage modification of medicinally relevant molecules. Mechanistic studies suggest a photocatalytically generated bromine radical can perform benzylic C−H cleavage to activate alkylarenes as nucleophilic coupling partners which can then engage in a nickel-catalyzed asymmetric acyl cross-coupling reaction. This bromine-radical-mediated C−H activation strategy can be also applied to the enantioselective coupling of alkylarenes with chloroformate for the synthesis of chiral α-aryl esters.

scholarly journals Integrating Allyl Electrophiles into Nickel-Catalyzed Conjunctive Cross-Coupling

2019 ◽  
Author(s):  
Van Tran ◽  
Zi-Qi Li ◽  
Timothy Gallagher ◽  
Joseph Derosa ◽  
Peng Liu ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Cross Coupling ◽  
Building Blocks ◽  
Reductive Elimination ◽  
Mechanistic Studies ◽  
Mild Conditions ◽  
Wide Range ◽  
Directing Group ◽  
Weakly Coordinating ◽  
Analogous Method

Allylation and conjunctive cross-coupling represent two useful, yet largely distinct, reactivity paradigms in catalysis. The union of these two processes would offer exciting possibilities in organic synthesis but remains largely unknown. Herein, we report the use of allyl electrophiles in nickel-catalyzed conjunctive cross-coupling with a non-conjugated alkene and dimethylzinc. The transformation is enabled by weakly coordinating, monodentate azaheterocycle directing groups, that useful building blocks in synthesis, including saccharin, pyridones, pyrazoles, and triazoles. The reaction occurs under mild conditions and is compatible with a wide range of allyl electrophiles. High chemoselectivity through substrate directivity is demonstrated in the facile reactivity of the β-γ alkene of the starting material, while the ε-ζ alkene of the product is preserved. The generality of this approach is further illustrated through the development of analogous method with alkyne substrates. Mechanistic studies reveal the importance of the weakly coordinating directing group in dissociating to allow binding of the allyl moiety to facilitate C(sp<sup>3</sup>)–C(sp<sup>3</sup>) reductive elimination.

Nickel-catalyzed oxidative cross-coupling of arylboronic acids with olefins

2014 ◽  
Vol 86 (3) ◽  
pp. 321-328 ◽  
Author(s):  
Dong Liu ◽  
Chao Liu ◽  
Aiwen Lei
Keyword(s):  
High Temperature ◽  
Boric Acid ◽  
Cross Coupling ◽  
Mechanistic Studies ◽  
Arylboronic Acids ◽  
Reaction Proceeds ◽  
Efficient Coupling ◽  
Styrene Derivatives ◽  
Acid Esters

Abstract A novel and efficient nickel-catalyzed oxidative cross-coupling of arylboronic acids with olefins to synthesize 1,2-diarylalkenes has been developed. By employing Ni(acac)2 as the catalyst, TEMPO (2,2,6,6-tetramethylpiperidine 1-oxyl) as the oxidant, a variety of arylboronic acids and styrene derivatives could be cross-coupled efficiently to afford the corresponding 1,2-diarylalkenes in moderate-to-good yields. Notably, high E-selectivity of 1,2-diarylalkenes was obtained with the aid of a high temperature of 120°C. Moreover, boric acid esters also proved to be efficient coupling partners. Initial mechanistic studies suggest that this reaction proceeds through a radical pathway.

scholarly journals Integrating Allyl Electrophiles into Nickel-Catalyzed Conjunctive Cross-Coupling

2019 ◽  
Author(s):  
Van Tran ◽  
Zi-Qi Li ◽  
Timothy Gallagher ◽  
Joseph Derosa ◽  
Peng Liu ◽  
...  
Keyword(s):  
Organic Synthesis ◽  
Cross Coupling ◽  
Building Blocks ◽  
Reductive Elimination ◽  
Mechanistic Studies ◽  
Mild Conditions ◽  
Wide Range ◽  
Directing Group ◽  
Weakly Coordinating ◽  
Analogous Method

Allylation and conjunctive cross-coupling represent two useful, yet largely distinct, reactivity paradigms in catalysis. The union of these two processes would offer exciting possibilities in organic synthesis but remains largely unknown. Herein, we report the use of allyl electrophiles in nickel-catalyzed conjunctive cross-coupling with a non-conjugated alkene and dimethylzinc. The transformation is enabled by weakly coordinating, monodentate azaheterocycle directing groups, that useful building blocks in synthesis, including saccharin, pyridones, pyrazoles, and triazoles. The reaction occurs under mild conditions and is compatible with a wide range of allyl electrophiles. High chemoselectivity through substrate directivity is demonstrated in the facile reactivity of the β-γ alkene of the starting material, while the ε-ζ alkene of the product is preserved. The generality of this approach is further illustrated through the development of analogous method with alkyne substrates. Mechanistic studies reveal the importance of the weakly coordinating directing group in dissociating to allow binding of the allyl moiety to facilitate C(sp<sup>3</sup>)–C(sp<sup>3</sup>) reductive elimination.

Sign in / Sign up

Export Citation Format

Share Document