Highly Regio- and Enantioselective Reductive Coupling of Alkynes and Aldehydes via Photoredox Cobalt Dual Catalysis

Liu, Yanlin; Zhang, Shiqi; Chen, Jie; Xia, Ji‐Bao

doi:10.1021/jacs.1c03527

Cited by 105 publications

(58 citation statements)

References 133 publications

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“…Based on the experimental data and previous studies in photoredox/cobalt catalysis, [14a–d,24] a plausible mechanism was proposed (Scheme 3, e). Frist, a single electron transfer (SET) from HE to the photoexcited 4‐CzIPN* generates HEH⋅ + (E ox (HE/EH⋅ + )=0.51 V vs. Fc in MeCN) [23e,25] and 4‐CzIPN⋅ − (E 1/2 red(4‐CzIPN*/4‐CzIPN⋅ − )=−1.21 V vs. SCE in MeCN) [26] .…”

Section: Resultsmentioning

confidence: 91%

“…Then the Co(II) catalyst precursor is reduced by 4‐CzIPN⋅ − giving a Co(I) species [14b,24b,c] . Meanwhile, EH⋅ + is deprotonated by the base (B) presented in the catalytic system generating HEH⋅, which is a highly reducing species and also capable of reducing 4‐CzIPN* to 4‐CzIPN⋅ − generating PyH + [14b,23a–e] . Thus, in this reaction HE performs as a two‐electron and two‐proton donor, and is superior to other stoichiometric electron donors [23d] .…”

Section: Resultsmentioning

confidence: 99%

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Direct Synthesis of Adipic Esters and Adiponitrile via Photoassisted Cobalt‐Catalyzed Alkene Hydrodimerization

Ren

2022

Chemistry A European J

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The direct hydrodimerization of acrylates and acrylonitrile offers a general streamlined access to industrially important intermediates to nylon 6,6. However, a practical catalytic method for this process has thus far underdeveloped owing to the challenges in regioselectivity and environmental compatibility of applied reagents. Here, we report a cobalt‐catalyzed tail‐to‐tail hydrodimerization of activated alkenes driven by a visible‐light photoredox catalysis at ambient temperature, which is applicable to both adipates and adiponitrile synthesis from potentially renewable feedstocks. This protocol utilizes half equivalent of hantzsch ester as a recyclable two‐electron and two‐proton donor with the assistance of catalytic amount of base as a proton shuttle, and has been shown to be highly regioselective and efficient for hydrodimerizing various activated alkenes to 1,4‐difunctionalized butane derivatives.

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Section: Resultsmentioning

confidence: 91%

Section: Resultsmentioning

confidence: 99%

Direct Synthesis of Adipic Esters and Adiponitrile via Photoassisted Cobalt‐Catalyzed Alkene Hydrodimerization

Ren

2022

Chemistry A European J

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“…Very recently, Xia and coworkers reported the first dual photoredox and cobalt catalyzed enantioselective coupling of aldehydes with internal alkynes using ( S , S)‐ BDPP as a chiral ligand (Scheme 30). [57] This method is amenable with aliphatic as well as aromatic aldehydes with either electron releasing or electron withdrawing substituents, affording excellent yields and high regio‐/enantioselective allylic alcohol. In the case of unsymmetrical alkynes, there was a very little effect of substituents on the enantioselectivity of the reaction.…”

Section: Co−h Insertion To Unsaturated C−c Bondsmentioning

confidence: 99%

Dual Photoredox and Cobalt Catalysis Enabled Transformations

Bajya

Selvakumar

2022

Eur J Org Chem

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Dual photoredox and cobalt catalysis opens a new and exciting avenue for transition metal catalyzed cross-coupling reaction. The ability of this approach to access low valent cobalt species gives enormous opportunity to develop reactions that relies on stoichiometric methods. In this mini review, we have compiled the most recent development of this dual catalytic system with particular attention paid to the mechanistic details and substrate scope. We hope that this review will be useful for synthetic organic chemists and further stimulate the advancement of more novel strategies.

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“…During these synthetic studies, we characterized several chiral [bis-phosphine]CoX 2 complexes by X-ray crystallography; among them, ( S , S -BDPP)CoCl 2 complex and a corresponding ligand-bridged Co(I)-complex, [( S , S )-BDPP] 3 Co 2 Cl 2 . In addition to the applications in our own work, the (BDPP)Co(II)-complex has since attracted significant attention for other cobalt-catalyzed enantioselective reactions …”

Section: Cobalt-catalyzed Heterodimerization Reactions Of 13-dienesmentioning

confidence: 99%

A New Paradigm in Enantioselective Cobalt Catalysis: Cationic Cobalt(I) Catalysts for Heterodimerization, Cycloaddition, and Hydrofunctionalization Reactions of Olefins

et al. 2021

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Conspectus One of the major challenges facing organic synthesis in the 21st century is the utilization of abundantly available feedstock chemicals for fine chemical synthesis. Regio- and enantioselective union of easily accessible 1,3-dienes and other feedstocks like ethylene, alkyl acrylates, and aldehydes can provide valuable building blocks adorned with latent functionalities for further synthetic elaboration. Through an approach that relies on mechanistic insights and systematic examination of ligand and counterion effects, we developed an efficient cobalt-based catalytic system [(P∼P)CoX2/Me3Al] (P∼P = bisphosphine) to effect the first enantioselective heterodimerization of several types of 1,3-dienes with ethylene. In addition to simple cyclic and acyclic dienes, siloxy-1,3-dienes participate in this reaction, giving highly functionalized, nearly enantiopure silyl enolates, which can be used for subsequent C–C and C–X bond-forming reactions. As our understanding of the mechanism of this reaction improved, our attention was drawn to more challenging partners like alkyl acrylates (one of the largest volume feedstocks) as the olefin partners instead of ethylene. Prompted by the intrinsic limitations of using aluminum alkyls as the activators for this reaction, we explored the fundamental chemistry of the lesser known (P∼P)Co(I)X species and discovered that in the presence of halide sequestering agents, such as sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBARF) or (C6F5)3B, certain chiral bisphosphine complexes are superb catalysts for regio- and enantioselective heterodimerization of 1,3-dienes and alkyl acrylates. We have since found that these cationic Co(I) catalysts, most conveniently prepared in situ by reduction of the corresponding cobalt(II) halide complexes by zinc in the presence of NaBARF, promote enantioselective [2 + 2]-cycloaddition between alkynes and an astonishing variety of alkenyl derivatives to give highly functionalized cyclobutenes. In reactions between 1,3-enynes and ethylene, the [2 + 2]-cycloaddition between the alkyne and ethylene is followed by a 1,4-addition of ethylene in a tandem fashion to give nearly enantiopure cyclobutanes with an all-carbon quaternary center, giving a set of molecules that maps well into many medicinally relevant compounds. In another application, we find that the cationic Co(I)-catalysts promote highly selective hydroacylation and 1,2-hydroboration of prochiral 1,3-dienes. Further, we find that a cationic Co(I)-catalyst promotes cycloisomerization followed by hydroalkenylation of 1,6-enynes to produce highly functionalized carbo- and heterocyclic compounds. Surprisingly the regioselectivity of the alkene addition depends on whether it is a simple alkene or an acrylate, and the acrylate addition produces an uncommon Z-adduct. This Account will provide a summary of the enabling basic discoveries and the attendant developments that led to the unique cationic Co(I)-complexes as catalysts for disparate C–C and C–B bond-forming reactions. It...

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Highly Regio- and Enantioselective Reductive Coupling of Alkynes and Aldehydes via Photoredox Cobalt Dual Catalysis

Cited by 105 publications

References 133 publications

Direct Synthesis of Adipic Esters and Adiponitrile via Photoassisted Cobalt‐Catalyzed Alkene Hydrodimerization

Direct Synthesis of Adipic Esters and Adiponitrile via Photoassisted Cobalt‐Catalyzed Alkene Hydrodimerization

Dual Photoredox and Cobalt Catalysis Enabled Transformations

A New Paradigm in Enantioselective Cobalt Catalysis: Cationic Cobalt(I) Catalysts for Heterodimerization, Cycloaddition, and Hydrofunctionalization Reactions of Olefins

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