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Kazimer L. Skubi

Bio: Kazimer L. Skubi is a academic researcher at Yale University who has co-authored 10 publication(s) receiving 1844 citation(s). The author has an hindex of 7. Previous affiliations of Kazimer L. Skubi include University of Wisconsin-Madison & Skidmore College. The author has done significant research in the topic(s): Enantioselective synthesis & Cycloaddition.

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Papers
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Open accessJournal ArticleDOI: 10.1021/ACS.CHEMREV.6B00018
25 Apr 2016-Chemical Reviews
Abstract: The interaction between an electronically excited photocatalyst and an organic molecule can result in the genertion of a diverse array of reactive intermediates that can be manipulated in a variety of ways to result in synthetically useful bond constructions. This Review summarizes dual-catalyst strategies that have been applied to synthetic photochemistry. Mechanistically distinct modes of photocatalysis are discussed, including photoinduced electron transfer, hydrogen atom transfer, and energy transfer. We focus upon the cooperative interactions of photocatalysts with redox mediators, Lewis and Bronsted acids, organocatalysts, enzymes, and transition metal complexes.

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1,299 Citations


Open accessJournal ArticleDOI: 10.1126/SCIENCE.1251511
25 Apr 2014-Science
Abstract: In contrast to the wealth of catalytic systems that are available to control the stereochemistry of thermally promoted cycloadditions, few similarly effective methods exist for the stereocontrol of photochemical cycloadditions. A major unsolved challenge in the design of enantioselective catalytic photocycloaddition reactions has been the difficulty of controlling racemic background reactions that occur by direct photoexcitation of substrates while unbound to catalyst. Here, we describe a strategy for eliminating the racemic background reaction in asymmetric [2 + 2] photocycloadditions of α,β-unsaturated ketones to the corresponding cyclobutanes by using a dual-catalyst system consisting of a visible light-absorbing transition-metal photocatalyst and a stereocontrolling Lewis acid cocatalyst. The independence of these two catalysts enables broader scope, greater stereochemical flexibility, and better efficiency than previously reported methods for enantioselective photochemical cycloadditions.

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350 Citations


Open accessJournal ArticleDOI: 10.1021/JACS.7B10586
Kazimer L. Skubi1, Jesse B. Kidd1, Hoimin Jung, Ilia A. Guzei1  +2 moreInstitutions (2)
Abstract: Stereochemical control of electronically excited states is a long-standing challenge in photochemical synthesis, and few catalytic systems that produce high enantioselectivities in triplet-state photoreactions are known. We report herein an exceptionally effective chiral photocatalyst that recruits prochiral quinolones using a series of hydrogen-bonding and π–π interactions. The organization of these substrates within the chiral environment of the transition-metal photosensitizer leads to efficient Dexter energy transfer and effective stereoinduction. The relative insensitivity of these organometallic chromophores toward ligand modification enables the optimization of this catalyst structure for high enantiomeric excess at catalyst loadings as much as 100-fold lower than the optimal conditions reported for analogous chiral organic photosensitizers.

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92 Citations


Open accessJournal ArticleDOI: 10.1021/JACS.9B06244
Jian Zheng1, Wesley B. Swords1, Wesley B. Swords2, Hoimin Jung3  +5 moreInstitutions (3)
Abstract: Enantioselective catalysis of excited-state photoreactions remains a substantial challenge in synthetic chemistry, and intermolecular photoreactions have proven especially difficult to conduct in a stereocontrolled fashion. Herein, we report a highly enantioselective intermolecular [2 + 2] cycloaddition of 3-alkoxyquinolones catalyzed by a chiral hydrogen-bonding iridium photosensitizer. Enantioselectivities as high as 99% ee were measured in reactions with a range of maleimides and other electron-deficient alkene reaction partners. An array of kinetic, spectroscopic, and computational studies supports a mechanism in which the photocatalyst and quinolone form a hydrogen-bonded complex to control selectivity, yet upon photoexcitation of this complex, energy transfer sensitization of maleimide is preferred. The sensitized maleimide then reacts with the hydrogen-bonded quinolone–photocatalyst complex to afford a highly enantioenriched cycloadduct. This finding contradicts a long-standing tenet of enantiosele...

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Topics: Enantioselective synthesis (53%), Maleimide (51%), Cycloaddition (50%)

49 Citations


Journal ArticleDOI: 10.1038/515045A
Kazimer L. Skubi1, Tehshik P. Yoon1Institutions (1)
06 Nov 2014-Nature
Abstract: The report of a light-activated catalyst that dictates the three-dimensional shape — the stereochemistry — of molecules formed in an organic reaction suggests a new strategy for controlling such reactions using visible light. See Letter p.100 The growing demand for optically active compounds in the chemical and pharmaceutical industries is focusing attention on asymmetric photocatalysis as a potentially economical means of synthesis, combining visible light photoredox chemistry with asymmetric catalysis. In this manuscript, the authors show that a chiral iridium complex can serve as a sensitizer for photoredox catalysis and at the same time provide effective asymmetric induction for the enantioselective alkylation of 2-acyl imidazoles. This new asymmetric photoredox catalyst, in which the metal centre serves simultaneously as the exclusive source of chirality, the catalytically active Lewis acid centre, and the photoredox centre, offers new opportunities for the 'green' synthesis of non-racemic chiral molecules.

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Topics: Photoredox catalysis (63%), Enantioselective synthesis (55%), Asymmetric induction (52%) ...read more

25 Citations


Cited by
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Open accessJournal ArticleDOI: 10.1021/ACS.CHEMREV.6B00018
25 Apr 2016-Chemical Reviews
Abstract: The interaction between an electronically excited photocatalyst and an organic molecule can result in the genertion of a diverse array of reactive intermediates that can be manipulated in a variety of ways to result in synthetically useful bond constructions. This Review summarizes dual-catalyst strategies that have been applied to synthetic photochemistry. Mechanistically distinct modes of photocatalysis are discussed, including photoinduced electron transfer, hydrogen atom transfer, and energy transfer. We focus upon the cooperative interactions of photocatalysts with redox mediators, Lewis and Bronsted acids, organocatalysts, enzymes, and transition metal complexes.

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1,299 Citations


Open accessJournal ArticleDOI: 10.1021/ACS.JOC.6B01449
Abstract: In recent years, photoredox catalysis has come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In a general sense, these approaches rely on the ability of metal complexes and organic dyes to convert visible light into chemical energy by engaging in single-electron transfer with organic substrates, thereby generating reactive intermediates. In this Perspective, we highlight the unique ability of photoredox catalysis to expedite the development of completely new reaction mechanisms, with particular emphasis placed on multicatalytic strategies that enable the construction of challenging carbon–carbon and carbon–heteroatom bonds.

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Topics: Photoredox catalysis (62%)

1,285 Citations


Journal ArticleDOI: 10.1021/ACS.CHEMREV.6B00644
Yoonsu Park, Youyoung Kim1, Sukbok Chang1Institutions (1)
04 Jan 2017-Chemical Reviews
Abstract: Catalytic transformation of ubiquitous C–H bonds into valuable C–N bonds offers an efficient synthetic approach to construct N-functionalized molecules. Over the last few decades, transition metal catalysis has been repeatedly proven to be a powerful tool for the direct conversion of cheap hydrocarbons to synthetically versatile amino-containing compounds. This Review comprehensively highlights recent advances in intra- and intermolecular C–H amination reactions utilizing late transition metal-based catalysts. Initial discovery, mechanistic study, and additional applications were categorized on the basis of the mechanistic scaffolds and types of reactions. Reactivity and selectivity of novel systems are discussed in three sections, with each being defined by a proposed working mode.

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Topics: Amination (52%)

1,150 Citations


Journal ArticleDOI: 10.1021/ACS.CHEMREV.8B00507
27 Feb 2019-Chemical Reviews
Abstract: C–H activation has surfaced as an increasingly powerful tool for molecular sciences, with notable applications to material sciences, crop protection, drug discovery, and pharmaceutical industries, among others. Despite major advances, the vast majority of these C–H functionalizations required precious 4d or 5d transition metal catalysts. Given the cost-effective and sustainable nature of earth-abundant first row transition metals, the development of less toxic, inexpensive 3d metal catalysts for C–H activation has gained considerable recent momentum as a significantly more environmentally-benign and economically-attractive alternative. Herein, we provide a comprehensive overview on first row transition metal catalysts for C–H activation until summer 2018.

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892 Citations


Journal ArticleDOI: 10.1038/S41570-017-0052
Jack Twilton1, Chi Chip Le1, Patricia Zhang1, Megan H. Shaw1  +2 moreInstitutions (1)
05 Jul 2017-
Abstract: The merger of transition metal catalysis and photocatalysis, termed metallaphotocatalysis, has recently emerged as a versatile platform for the development of new, highly enabling synthetic methodologies. Photoredox catalysis provides access to reactive radical species under mild conditions from abundant, native functional groups, and, when combined with transition metal catalysis, this feature allows direct coupling of non-traditional nucleophile partners. In addition, photocatalysis can aid fundamental organometallic steps through modulation of the oxidation state of transition metal complexes or through energy-transfer-mediated excitation of intermediate catalytic species. Metallaphotocatalysis provides access to distinct activation modes, which are complementary to those traditionally used in the field of transition metal catalysis, thereby enabling reaction development through entirely new mechanistic paradigms. This Review discusses key advances in the field of metallaphotocatalysis over the past decade and demonstrates how the unique mechanistic features permit challenging, or previously elusive, transformations to be accomplished. Transition metal catalysis is well established as an enabling tool in synthetic organic chemistry. Photoredox catalysis has recently emerged as a method to effect reactions that occur through single-electron-transfer pathways. Here we review the combination of the two to show how this provides access to highly reactive oxidation states of transition metals and distinct activation modes that further enable the synthetic chemist.

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Topics: Photoredox catalysis (54%)

892 Citations


Performance
Metrics

Author's H-index: 7

No. of papers from the Author in previous years
YearPapers
20211
20201
20192
20182
20171
20161

Top Attributes

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Author's top 5 most impactful journals

Biochemistry

1 papers, 9 citations

Nature

1 papers, 25 citations

Inorganic Chemistry

1 papers, 3 citations

Science

1 papers, 350 citations

Network Information
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