scholarly journals The A3 Redox-Neutral C1-Alkynylation of Tetrahydroisoquinolines: A Comparative Study between Visible Light Photocatalysis and Transition-Metal Catalysis

Synthesis ◽  
2020 ◽  
Author(s):  
Vladimir V. Kouznetsov ◽  
Marlyn C. Ortiz Villamizar ◽  
Carlos E. Puerto Galvis
Keyword(s):  
Transition Metal ◽  
Microwave Irradiation ◽  
Visible Light ◽  
High Selectivity ◽  
Transition Metal Catalysis ◽  
Visible Light Photocatalysis ◽  
Reaction Conditions ◽  
Metal Catalysis ◽  
New Compounds ◽  
Optimal Reaction

AbstractConsidering the current challenges of the A3 redox-neutral C1-alkynylation of tetrahydroisoquinolines (THIQs), we studied this synthetic tool under visible light photocatalysis and transition-metal catalysis in order to describe alternative reaction conditions and discuss possible improvements to this process. We demonstrated that 1-alkynylated THIQs can be readily obtained by three different approaches: iridium-based photocatalysis and copper ([CuBr(PPh3)3]) and silver (AgNO3) catalysis under mild, selective and accessible reaction conditions. Among these approaches, the copper(I)-based methodology resulted in the most robust, optimal reaction conditions for the synthesis of a series of 18 1-alkynylated THIQs in moderate to excellent yields and with high selectivity for the endo-alkynylated products. Moreover, this reaction can be accelerated by microwave irradiation (120 °C, 15 min) affording a novel library of diverse THIQs with alkyne and N-substituent moieties, from unreactive and uncommon substrates, that could be further transformed into new compounds of interest.

1.2.1 General Principles of Transition-Metal/Photocatalyst Dual Catalysis

2020 ◽  
Author(s):  
J. C. Tellis
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Transition Metal Catalysis ◽  
Specific Role ◽  
Visible Light Photocatalysis ◽  
Metal Catalysis ◽  
Catalytic Transformations ◽  
Dual Catalysis

AbstractThe combination of transition-metal catalysis and visible-light photocatalysis offers opportunities for the development of unique new forms of reactivity. Presented in this chapter is an overview of the various strategies that can be used to design these dual catalytic transformations. Emphasis is placed on understanding the specific role that a photocatalyst can play in augmenting the reactivity of a substrate or cocatalyst to achieve otherwise challenging transformations.

Merging Transition-Metal Catalysis with Photoredox Catalysis: An Environmentally Friendly Strategy for C–H Functionalization

Synthesis ◽  
2018 ◽  
Vol 50 (17) ◽  
pp. 3359-3378 ◽  
Author(s):  
Wen-Jun Zhou ◽  
Da-Gang Yu ◽  
Yi-Han Zhang ◽  
Yong-Yuan Gui ◽  
Liang Sun
Keyword(s):  
Transition Metal ◽  
High Selectivity ◽  
Rapid Development ◽  
Palladium Catalysis ◽  
Transition Metal Catalysis ◽  
Nickel Catalysis ◽  
Photoredox Catalysis ◽  
Reaction Conditions ◽  
Metal Catalysis ◽  
Metal Catalyzed

Transition-metal-catalyzed C–H functionalization is already a useful tool in organic synthesis, whilst the rapid development of photoredox catalysis provides new pathways for C–H functionalization with high selectivity and efficiency under mild reaction conditions. In this review, recent advances in C–H functionalization through merging transition­-metal catalysis with photoredox catalysis are discussed.1 Introduction2 Merging Nickel Catalysis with Photoredox Catalysis3 Merging Palladium Catalysis with Photoredox Catalysis4 Merging Cobalt Catalysis with Photoredox Catalysis5 Merging Photoredox Catalysis with Other Transition-Metal Catalysis­6 Conclusions

Visible Light-Induced Transition Metal Catalysis

2021 ◽  
Author(s):  
Kelvin Pak Shing Cheung ◽  
Sumon Sarkar ◽  
Vladimir Gevorgyan
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Transition Metal Catalysis ◽  
Metal Catalysis

scholarly journals TiO2 Photocatalyzed C–H Bond Transformation for C–C Coupling Reactions

Catalysts ◽  
2018 ◽  
Vol 8 (9) ◽  
pp. 355 ◽  
Author(s):  
Yi Wang ◽  
Anan Liu ◽  
Dongge Ma ◽  
Shuhong Li ◽  
Chichong Lu ◽  
...  
Keyword(s):  
Transition Metal ◽  
Visible Light ◽  
Visible Light Irradiation ◽  
Transition Metal Catalysis ◽  
Light Irradiation ◽  
Coupling Reactions ◽  
Metal Catalysis ◽  
Bond Functionalization ◽  
Tio2 Photocatalysis ◽  
Mild Conditions

Fulfilling the direct inert C–H bond functionalization of raw materials that are earth-abundant and commercially available for the synthesis of diverse targeted organic compounds is very desirable and its implementation would mean a great reduction of the synthetic steps required for substrate prefunctionalization such as halogenation, borylation, and metalation. Successful C–H bond functionalization mainly resorts to homogeneous transition-metal catalysis, albeit sometimes suffering from poor catalyst reusability, nontrivial separation, and severe biotoxicity. TiO2 photocatalysis displays multifaceted advantages, such as strong oxidizing ability, high chemical stability and photostability, excellent reusability, and low biotoxicity. The chemical reactions started and delivered by TiO2 photocatalysts are well known to be widely used in photocatalytic water-splitting, organic pollutant degradation, and dye-sensitized solar cells. Recently, TiO2 photocatalysis has been demonstrated to possess the unanticipated ability to trigger the transformation of inert C–H bonds for C–C, C–N, C–O, and C–X bond formation under ultraviolet light, sunlight, and even visible-light irradiation at room temperature. A few important organic products, traditionally synthesized in harsh reaction conditions and with specially functionalized group substrates, are continuously reported to be realized by TiO2 photocatalysis with simple starting materials under very mild conditions. This prominent advantage—the capability of utilizing cheap and readily available compounds for highly selective synthesis without prefunctionalized reactants such as organic halides, boronates, silanes, etc.—is attributed to the overwhelmingly powerful photo-induced hole reactivity of TiO2 photocatalysis, which does not require an elevated reaction temperature as in conventional transition-metal catalysis. Such a reaction mechanism, under typically mild conditions, is apparently different from traditional transition-metal catalysis and beyond our insights into the driving forces that transform the C–H bond for C–C bond coupling reactions. This review gives a summary of the recent progress of TiO2 photocatalytic C–H bond activation for C–C coupling reactions and discusses some model examples, especially under visible-light irradiation.

scholarly journals Sulfoxonium Ylide Derived Metal Carbenoids in Organic Synthesis

Synthesis ◽  
2018 ◽  
Vol 51 (03) ◽  
pp. 612-628 ◽  
Author(s):  
Janakiram Vaitla ◽  
Annette Bayer
Keyword(s):  
Transition Metal ◽  
Organic Synthesis ◽  
Transition Metal Catalysis ◽  
Transfer Reactions ◽  
Reaction Conditions ◽  
Widespread Application ◽  
Metal Catalysis ◽  
Half Century ◽  
Metal Carbenoids

As pioneered by Corey and Chaykovsky, sulfoxonium ylides have had widespread application in organic synthesis for more than a half century. In most of the reactions, sulfoxonium ylides were used to react with electrophiles. Under suitable reaction conditions these ylides can generate metal carbenoids and react with nucleophiles. By combining the typical reactivity of sulfoxonium ylides with transition-metal catalysis, a growing number of investigations have expanded their application in organic synthesis. This review provides an update on the preparation of sulfoxonium ylides and their applications in carbenoid transfer reactions.1 Introduction2 Preparation of Sulfoxonium Ylides3 Investigation for Carbenoid Formation from Sulfoxonium Ylide 4 X–H (X = N, O, S, C) Functionalization Reactions5 Polymerizaton of Carbenoids Generated from Sulfoxonium Ylides6 Conclusion and Perspective

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