Single Electron Transfer-Induced Redox Processes Involving N-(Acyloxy)phthalimides

ACS Catalysis, Год журнала: 2021, Номер 11(3), С. 1640 - 1683

Опубликована: Янв. 20, 2021

The past decade has witnessed the emergence of N-(acyloxy)phthalimides (NHPI esters) and its derivatives at forefront synthetic methods facilitating construction diverse molecular frameworks from readily available carboxylic acid feedstock. NHPI esters are predisposed to undergo reductive fragmentation via a single electron transfer (SET) process under thermal, photochemical, or electrochemical conditions generate corresponding carbon- nitrogen-centered radicals that participate in multitude transformations forge carbon–carbon carbon–heteroatom bonds. chemistry involving received broad applicability not only well-designed cascade annulations but also medicinal natural product synthesis. This comprehensive Review, broadly categorized according nature bond formation, details progress made this field since initial discovery by providing representative examples with mechanistic details, an emphasis on challenges future directions.

Язык: Английский

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Selective Carbon–Carbon Bond Cleavage of Cyclopropanols

Chemical Reviews, Год журнала: 2020, Номер 121(1), С. 3 - 79

Опубликована: Окт. 21, 2020

The carbon–carbon (C–C) bond cleavage of cyclopropanols is a wide area research with much current activity. This review highlights new developments in this over the past two decades. A summary made three main reactivity modes, namely, homoenolate chemistry, β-keto radical and acid-catalyzed ring-opening, as well all other methods for C–C functionalization cyclopropanols, including base-mediated metal-catalyzed insertions eliminations, oxidative fragmentation using hypervalent iodine reagents, reactions donor–acceptor pericylic reactions. Emphasis placed on synthetic utility related derivatives, which have emerged unique three-carbon synthons.

Язык: Английский

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On the Origin of Rh-Catalyzed Selective Ring-Opening Amidation of Substituted Cyclopropanols to Access β²-Amino Ketones

Journal of the American Chemical Society, Год журнала: 2022, Номер 144(8), С. 3667 - 3675

Опубликована: Фев. 15, 2022

β2-Amino carbonyls, an α-substituted β-amino scaffold, hold a prominent place in the development of new pharmaceuticals and peptidomimetics. Herein, we report highly efficient Rh-catalyzed ring-opening amidation substituted cyclopropanols, which turned out to serve as linchpin for selective synthesis β2-amino ketones outcompete formation β3-isomers. Instead generally accepted rationale consider steric factors β2-selectivity, orbital interaction was elucidated play more critical role amidative cyclopropanols generate key Rh–C intermediate. Subsequent inner-sphere acylnitrene transfer achieved excellent efficiency (TON > 5000) by using readily accessible dioxazolones amino source afford with broad applicability.

Язык: Английский

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Effect of 6,6′-Substituents on Bipyridine-Ligated Ni Catalysts for Cross-Electrophile Coupling

ACS Catalysis, Год журнала: 2024, Номер 14(9), С. 6897 - 6914

Опубликована: Апрель 19, 2024

A family of 4,4′-tBu2-2,2′-bipyridine (tBubpy) ligands with substituents in either the 6-position, 4,4′-tBu2-6-Me-bpy (tBubpyMe), or 6 and 6′-positions, 4,4′-tBu2-6,6′-R2-bpy (tBubpyR2; R = Me, iPr, sBu, Ph, Mes), was synthesized. These were used to prepare Ni complexes 0, I, II oxidation states. We observed that 6′-positions tBubpy ligand impact properties complexes. For example, bulkier 6,6′-positions better stabilized (tBubpyR2)NiICl species resulted a cleaner reduction from (tBubpyR2)NiIICl2. However, hindered prevented coordination tBubpyR2 Ni0(cod)2. In addition, by using type (tBubpyMe)NiCl2 (tBubpyR2)NiCl2 as precatalysts for different XEC reactions, we demonstrated 6,6′-substituents lead major differences catalytic performance. Specifically, while (tBubpyMe)NiIICl2 is one most active catalysts reported date can facilitate reactions at room temperature, lower turnover frequencies containing ligands. detailed study on intermediates (tBubpy)Ni(Ar)I (tBubpyMe2)Ni(Ar)I revealed several factors likely contributed activity. whereas are low spin relatively stable, high-spin less stable. Furthermore, captures primary benzylic alkyl radicals more slowly than (tBubpy)Ni(Ar)I, consistent activity former catalysis. Our findings will assist design tailor-made Ni-catalyzed transformations.

Язык: Английский

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Ni-Catalyzed Denitrogenative Cross-Coupling of Benzotriazinones and Cyclopropanols: An Easy Access to Functionalized β-Aryl Ketones

Organic Letters, Год журнала: 2020, Номер 22(13), С. 5020 - 5024

Опубликована: Июнь 11, 2020

A novel Ni-catalyzed denitrogenative cross-coupling between benzotriazinones and cyclopropanols is reported herein. This neoteric reactivity allows for the convenient synthesis of β-(o-amido)aryl ketones from readily available starting materials with good yields (up to 93%) general substrate scope.

Язык: Английский

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Metal-Catalyzed Transformations of Cyclopropanols via Homoenolates

Bulletin of the Chemical Society of Japan, Год журнала: 2020, Номер 94(1), С. 265 - 280

Опубликована: Сен. 28, 2020

Abstract Metal homoenolates represent uniquely useful organometallic intermediates in synthetic chemistry, allowing umpolung synthesis of β-functionalized carbonyl compounds. While siloxycyclopropanes had been established as reliable precursors to homoenolates, often stoichiometric, for diverse carbon–carbon bond forming reactions, unprotected cyclopropanols have emerged alternative and attractive catalytically generated, carbon–heteroatom bond-forming reactions. This review article provides an overview the development such homoenolate transformations, classified with respect metals involved cyclopropane ring opening.

Язык: Английский

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Nickel-Catalyzed Carbonylation of Cyclopropanol with Benzyl Bromide for Multisubstituted Cyclopentenone Synthesis

Organic Letters, Год журнала: 2022, Номер 24(14), С. 2699 - 2704

Опубликована: Апрель 7, 2022

Herein, we reported a Ni-catalyzed carbonylation of cyclopropanol with benzyl bromide to afford multisubstituted cyclopentenone under 1 atm CO. The reaction proceeds through cascade bromides, followed by generation nickel homoenolate from cyclopropanols via β-C elimination 1,4-diketones, which undergoes intramolecular Aldol condensation furnish highly substituted derivatives in moderate good yields. exhibits high functional group tolerance broad substrate scope.

Язык: Английский

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Enantioselective Copper‐Catalyzed Radical Ring‐Opening Cyanation of Cyclopropanols and Cyclopropanone Acetals

Advanced Synthesis & Catalysis, Год журнала: 2020, Номер 362(11), С. 2189 - 2194

Опубликована: Март 17, 2020

Abstract A novel approach for enantioselective cyanation of cyclopropanols and their derivatives through copper‐catalyzed radical relay processes has been developed. Various cyclopropanone acetals are compatible to the catalytic conditions, providing β‐carbonyl nitriles with excellent enantioselectivity. These products can be readily converted chiral γ‐amino acids drugs such as (R)‐baclofen. Preliminary mechanistic studies have supported a ring‐opening process cyclopropanoxy radicals followed by benzylic form C−CN bonds in an manner. magnified image

Язык: Английский

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The Cyclopropane Ring as a Reporter of Radical Leaving-Group Reactivity for Ni-Catalyzed C(sp³)–O Arylation

Journal of the American Chemical Society, Год журнала: 2020, Номер 142(30), С. 13246 - 13254

Опубликована: Июль 1, 2020

The ability to understand and predict reactivity is essential for the development of new reactions. In context Ni-catalyzed C(sp3)–O functionalization, we have developed a unique strategy employing activated cyclopropanols aid design optimization redox-active leaving group arylation. this chemistry, cyclopropane ring acts as reporter leaving-group reactivity, since ring-opened product obtained under polar (2e) conditions, ring-closed radical (1e) conditions. Mechanistic studies demonstrate that optimal are consistent with Ni(I)/Ni(III) catalytic cycle. optimized reaction conditions also used synthesize number arylcyclopropanes, which valuable pharmaceutical motifs.

Язык: Английский

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Rhodium-Catalyzed Room Temperature C–C Activation of Cyclopropanol for One-Step Access to Diverse 1,6-Diketones

Organic Letters, Год журнала: 2020, Номер 22(7), С. 2854 - 2860

Опубликована: Март 25, 2020

A rhodium-catalyzed room temperature C-C activation of cyclopropanol has been demonstrated for the single-step synthesis a range electronically and sterically distinct 1,6-diketones. This reaction proceeds efficiently in shorter time following highly atom-economical pathway. To illustrate synthetic potential 1,6-diketones, aldol macrocyclization reactions have successfully demonstrated. Preliminary mechanistic studies revealed involvement nonradical pathways.

Язык: Английский

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