Photoredox-Mediated Asymmetric Cross-Dehydrogenative Coupling of Enones and Tertiary Amines by Chiral Primary Amine Catalysis

Jia, Zongbin; Qi, Yang; Luo, Sanzhong

doi:10.1055/a-1463-4219

Cited by 6 publications

(2 citation statements)

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“…Later in 2021, we realized a similar process in the asymmetric cross-dehydrogenative coupling of enones and tetrahydroisoquinolines, which is known as the Morita−Baylis− Hillman (MBH)-type reaction (Scheme 11). 62 Decarboxylative Alkynylation. Other than substrates, chiral enamine intermediates can also react with excited-state PS and generate high-energy species to facilitate the asymmetric catalysis process.…”

Section: Photoredox Catalysismentioning

confidence: 99%

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

Cai,

Zhang,

Zhang

et al. 2024

Acc. Chem. Res.

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Metrics & MoreArticle Recommendations CONSPECTUS: Synergistic catalysis is a powerful tool that involves two or more distinctive catalytic systems to activate reaction partners simultaneously, thereby expanding the reactivity space of individual catalysis. As an established catalytic strategy, organocatalysis has found numerous applications in enantioselective transformations under rather mild conditions.Recently, the introduction of other catalytic systems has significantly expanded the reaction space of typical organocatalysis. In this regard, aminocatalysis is a prototypical example of synergistic catalysis. The combination of aminocatalyst and transition metal could be traced back to the early days of organocatalysis and has now been well explored as an enabling catalytic strategy. Particularly, the acid−base properties of aminocatalysis can be significantly expanded to include usually electrophiles generated in situ via metal-catalyzed cycles. Later on, aminocatalyst has also been exploited in synergistically combining with photochemical and electrochemical processes to facilitate redox transformations. However, synergistically combining one type of aminocatalyst with many different catalytic systems remains a great challenge. One of the most daunting challenges is the compatibility of aminocatalysts in coexistence with other catalytic species. As nucleophilic species, aminocatalysts may also bind with metal, which leads to mutual inhibition or even quenching of the individual catalytic activity. In addition, oxidative stability of aminocatalyst is also a nonneglectable issue, which causes difficulties in exploring oxidative enamine transformations.In 2007, we developed a vicinal diamine type of chiral primary aminocatalysts. This class of primary aminocatalysts was developed and evolved as functional and mechanistic mimics to the natural aldolase and has been widely applied in a number of enamine/ iminium ion-based transformations. By following a "1 + x" synergistic strategy, the chiral primary amine catalysts were found to work synergistically or cooperatively with a number of transition metal catalysts, such as Pd, Rh, Ag, Co, and Cu, or other organocatalysts, such as B(C 6 F 5 ) 3 , ketone, selenium, and iodide. Photocatalysis and electrochemical processes can also be incorporated to work together with the chiral primary amine catalysts. The 1 + x catalytic strategy enabled us to execute unexploited transformations by fine-tuning the acid−base and redox properties of the enamine intermediates and to achieve effective reaction and stereocontrol beyond the reach individually. During these efforts, an unprecedented excited-state chemistry of enamine was uncovered to make possible an effective deracemization process. In this Account, we describe our recent efforts since 2015 in exploring synergistic chiral primary amine catalysis, and the content is categorized according to the type of synergistic partner such that in each section the developed synergistic catalysis, reaction scopes, and mechanistic features...

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Section: Photoredox Catalysismentioning

confidence: 99%

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

Cai,

Zhang,

Zhang

et al. 2024

Acc. Chem. Res.

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“…Among these reports, the catalytic oxidation of C(sp 3 )–H bonds adjacent to nitrogen affords active iminium ions and is a powerful strategy for amine functionalization. ,, As the tetrahydroisoquinoline skeleton is an essential structural unit in pharmaceutical and natural products (Scheme a), N -aryl-tetrahydroisoquinoline (THIQ) has been widely employed as the substrate to verify the feasibility of the oxidative coupling strategy. Pioneered by Li and Murahashi’s studies on the oxidative coupling of tertiary amines with various nucleophiles and Stephenson’s alternative work via photoredox catalysis, a variety of elegant reports have been made in the attractive field, though stoichiometric oxidants or expensive metal photoredox catalysts were needed (Scheme b). , Wang and co-workers developed an organocatalysis/copper-catalyzed asymmetric oxidative C(sp 3 )–H alkenylation of THIQs using the molecule as the sole oxidant despite long reaction times (24–72 h). , Later, photoredox catalysts were employed for direct C1–H olefination of THIQs, which also needed days for the reactions to proceed, and some of them needed to avoid light in a later stage, and some of them needed to avoid air or moisture. In an attempt to overcome these drawbacks and also as part of our ongoing interest in organic electrosynthesis, recently, our group developed the alkenylation of tetrahydroisoquinolines via electrosynthesis, which did not involve asymmetric induction.…”

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confidence: 99%

C(sp³)–H Aerobic Alkenylation of Tetrahydroisoquinolines via Organic Electrosynthesis

Liu

Wang

et al. 2023

J. Org. Chem.

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A method for the C(sp 3 )−H alkenylation of N-aryltetrahydroisoquinoline (THIQ) has been developed by the combination of electrooxidation and a copper catalyst. The corresponding products were obtained with good to excellent yields under mild conditions. Besides, the addition of TEMPO as an electron mediator is crucial to this transformation, since the oxidative reaction could proceed under a low electrode potential. In addition, the catalytic asymmetric variant has also been demonstrated with good enantioselectivity.

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Electrochemically‐Driven Organocatalytic Enantioselective Oxidative Coupling of Tetrahydroisoquinolines and Acrylaldehyde

Zhang,

Li,

Wang

et al. 2023

Adv Synth Catal

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An electrochemically‐driven organocatalytic enantioselective oxidative coupling of tetrahydroisoquin‐olines and acrylaldehyde was developed. Various chiral C1‐alkenyl tetrahydroisoquinolines derivatives were obtained with 69‐86% yields and 93:7‐96:4 er. Notable features of this reaction include asymmetric organocatalysis (5.0 mol% β‐ICD as catalyst), electricity as the oxidant, air atmosphere, and undivided cell. This synthetic route offers straightforward access to various optically active C1‐substituted tetrahydroisoquinolines derivatives.

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Photoredox-Mediated Asymmetric Cross-Dehydrogenative Coupling of Enones and Tertiary Amines by Chiral Primary Amine Catalysis

Cited by 6 publications

References 2 publications

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

C(sp³)–H Aerobic Alkenylation of Tetrahydroisoquinolines via Organic Electrosynthesis

Electrochemically‐Driven Organocatalytic Enantioselective Oxidative Coupling of Tetrahydroisoquinolines and Acrylaldehyde

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Photoredox-Mediated Asymmetric Cross-Dehydrogenative Coupling of Enones and Tertiary Amines by Chiral Primary Amine Catalysis

Cited by 6 publications

References 2 publications

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

Enantioselective Transformations by “1 + x” Synergistic Catalysis with Chiral Primary Amines

C(sp3)–H Aerobic Alkenylation of Tetrahydroisoquinolines via Organic Electrosynthesis

Electrochemically‐Driven Organocatalytic Enantioselective Oxidative Coupling of Tetrahydroisoquinolines and Acrylaldehyde

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C(sp³)–H Aerobic Alkenylation of Tetrahydroisoquinolines via Organic Electrosynthesis