Recent Progress in Metal-Catalyzed [2+2+2] Cycloaddition Reactions

Synthesis ◽  
2021 ◽  
Author(s):  
Virginie Ratovelomanana-Vidal ◽  
Pascal Matton ◽  
Steve Huvelle ◽  
Mansour Haddad ◽  
Phannarath Phansavath
Keyword(s):  
Functional Group ◽  
Single Step ◽  
Organometallic Complexes ◽  
Cycloaddition Reactions ◽  
Planar Chirality ◽  
Rapid Construction ◽  
Intramolecular Reactions ◽  
Intermolecular Reactions ◽  
Metal Catalyzed ◽  
Economical Process

AbstractMetal-catalyzed [2+2+2] cycloaddition is a powerful tool that allows rapid construction of functionalized 6-membered carbo- and heterocycles in a single step through an atom-economical process with high functional group tolerance. The reaction is usually regio- and chemoselective although selectivity issues can still be challenging for intermolecular reactions involving the cross-[2+2+2] cycloaddition of two or three different alkynes and various strategies have been developed to attain high selectivities. Furthermore, enantioselective [2+2+2] cycloaddition is an efficient means to create central, axial, and planar chirality and a variety of chiral organometallic complexes can be used for asymmetric transition-metal-catalyzed inter- and intramolecular reactions. This review summarizes the recent advances in the field of [2+2+2] cycloaddition.1 Introduction2 Formation of Carbocycles2.1 Intermolecular Reactions2.1.1 Cyclotrimerization of Alkynes2.1.2 [2+2+2] Cycloaddition of Two Different Alkynes2.1.3 [2+2+2] Cycloaddition of Alkynes/Alkenes with Alkenes/Enamides2.2 Partially Intramolecular [2+2+2] Cycloaddition Reactions2.2.1 Rhodium-Catalyzed [2+2+2] Cycloaddition2.2.2 Molybdenum-Catalyzed [2+2+2] Cycloaddition2.2.3 Cobalt-Catalyzed [2+2+2] Cycloaddition2.2.4 Ruthenium-Catalyzed [2+2+2] Cycloaddition2.2.5 Other Metal-Catalyzed [2+2+2] Cycloaddition2.3 Totally Intramolecular [2+2+2] Cycloaddition Reactions3 Formation of Heterocycles3.1 Cycloaddition of Alkynes with Nitriles3.2 Cycloaddition of 1,6-Diynes with Cyanamides3.3 Cycloaddition of 1,6-Diynes with Selenocyanates3.4 Cycloaddition of Imines with Allenes or Alkenes3.5 Cycloaddition of (Thio)Cyanates and Isocyanates3.6 Cycloaddition of 1,3,5-Triazines with Allenes3.7 Cycloaddition of Aldehydes with Enynes or Allenes/Alkenes3.8 Totally Intramolecular [2+2+2] Cycloaddition Reactions4 Conclusion

scholarly journals Protecting group-free, selective cross-coupling of alkyltrifluoroborates with borylated aryl bromides via photoredox/nickel dual catalysis

2015 ◽  
Vol 112 (39) ◽  
pp. 12026-12029 ◽  
Author(s):  
Yohei Yamashita ◽  
John C. Tellis ◽  
Gary A. Molander
Keyword(s):  
Small Molecules ◽  
Functional Group ◽  
Cross Coupling ◽  
Differential Protection ◽  
Coupling Reactions ◽  
Protecting Group ◽  
Cross Coupling Reactions ◽  
Aryl Bromides ◽  
Rapid Construction ◽  
Metal Catalyzed

Orthogonal reactivity modes offer substantial opportunities for rapid construction of complex small molecules. However, most strategies for imparting orthogonality to cross-coupling reactions rely on differential protection of reactive sites, greatly reducing both atom and step economies. Reported here is a strategy for orthogonal cross-coupling wherein a mechanistically distinct activation mode for transmetalation of sp3-hybridized organoboron reagents enables C-C bond formation in the presence of various protected and unprotected sp2-hybridized organoborons. This manifold has the potential for broad application, because orthogonality is inherent to the activation mode itself. The diversification potential of this platform is shown in the rapid elaboration of a trifunctional lynchpin through various transition metal-catalyzed processes without nonproductive deprotection or functional group manipulation steps.

scholarly journals Recent Advances in Palladium-Catalyzed Bridging C–H Activation by Using Alkenes, Alkynes or Diazo Compounds as Bridging Reagents

Synthesis ◽  
2020 ◽  
Vol 53 (02) ◽  
pp. 238-254
Author(s):  
Fulin Zhang ◽  
Luoting Xin ◽  
Saihu Liao ◽  
Xueliang Huang ◽  
Yinghua Yu
Keyword(s):  
Bond Distance ◽  
Short Review ◽  
Diazo Compounds ◽  
Bond Functionalization ◽  
Migratory Insertion ◽  
Intramolecular Reactions ◽  
Palladium Catalyzed ◽  
Direct Functionalization ◽  
Intermolecular Reactions ◽  
Metal Catalyzed

AbstractTransition-metal-catalyzed direct inert C–H bond functionalization has attracted much attention over the past decades. However, because of the high strain energy of the suspected palladacycle generated via C–H bond palladation, direct functionalization of a C–H bond less than a three-bond distance from a catalyst center is highly challenging. In this short review, we summarize the advances on palladium-catalyzed bridging C–H activation, in which an inert proximal C–H bond palladation is promoted by the elementary step of migratory insertion of an alkene, an alkyne or a metal carbene intermediate.1 Introduction2 Palladium-Catalyzed Alkene Bridging C–H Activation2.1 Intramolecular Reactions2.2 Intermolecular Reactions3 Palladium-Catalyzed Alkyne Bridging C–H Activation3.1 Intermolecular Reactions3.2 Intramolecular Reactions4 Palladium-Catalyzed Carbene Bridging C–H Activation5 Conclusion and Outlook

Catalytic Enantioselective Benzylation Directly from Aryl Acetic Acids

2018 ◽  
Author(s):  
Patrick Moon ◽  
Zhongyu Wie ◽  
Rylan Lundgren
Keyword(s):  
Functional Group ◽  
Terminal Event ◽  
Radical Intermediates ◽  
Carbon Carbon Bond ◽  
Or Groups ◽  
Reaction Proceeds ◽  
Wide Availability ◽  
Metal Catalyzed ◽  
The Stability ◽  
Acetic Acids

The stability and wide availability of carboxylic acids make them valuable reagents in chemical synthesis. Most transition metal catalyzed processes using carboxylic acid substrates are initiated by a decarboxylation event that generates reactive carbanion or radical intermediates. Developing enantioselective methodologies relying on these principles can be challenging, as highly reactive species tend to react indiscriminately without selectivity. Furthermore, anionic or radical intermediates generated from decarboxylation can be incompatible with protic and electrophilic functionality, or groups that undergo trapping with radicals. We demonstrate that metal-catalyzed enantioselective benzylation reactions of allylic electrophiles can occur directly from aryl acetic acids. The reaction proceeds via a pathway in which decarboxylation is the terminal event, occurring after stereoselective carbon–carbon bond formation. The mechanistic features of the process enable enantioselective benzylation without the generation of a highly basic nucleophile. Thus, the process has broad functional group compatibility that would not be possible employing established protocols.<br>

Asymmetric Synthesis of α-Alkylated γ-Lactam via Nickel/8-Quinim-Catalyzed Reductive Alkyl-Carbamoylation of Unactivated Alkene

Synlett ◽  
2021 ◽  
Author(s):  
Xianqing Wu ◽  
Mohini Shrestha ◽  
Yifeng Chen
Keyword(s):  
Functional Group ◽  
Enantioselective Synthesis ◽  
Chiral Auxiliary ◽  
Alkyl Iodide ◽  
General Strategy ◽  
Chemical Bonds ◽  
Mild Conditions ◽  
Chiral Carbon ◽  
Enantioselective Reaction ◽  
Metal Catalyzed

AbstractChiral-auxiliary-mediated synthesis represents the most frequently used synthetic tool for the induction of chirality on α-position of γ-lactams in organic synthesis. However, the general strategy requires the stoichiometric use of chiral reagents with multiple manipulation steps. Transition-metal-catalyzed asymmetric alkene dicarbofunctionalization using readily available substrates under mild conditions allows the simultaneous construction of two vicinal chemical bonds and a chiral carbon center, hence, gain expedient access to chiral heterocycles. Herein, we disclose a Ni-catalyzed enantioselective reaction of 3-butenyl carbamoyl chloride and primary alkyl iodide enabled by a newly designed chiral 8-quinoline imidazoline ligand (8-Quinim). This protocol features broad functional group tolerance and high enantioselectivities, achieving unprecedented synthesis of chiral nonaromatic heterocycles via catalytic reductive protocol.1 Introduction2 Development of 8-Quinim Ligand3 Nickel/8-Quinim-Catalyzed Enantioselective Synthesis of Chiral α-Alkylated γ-Lactam4 Conclusion and Outlook

scholarly journals Palladium-Catalysed Synthesis and Transformation of Quinolones

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 228 ◽  
Author(s):  
Vera L. M. Silva ◽  
Artur M. S. Silva
Keyword(s):  
Multiple Bond ◽  
Single Step ◽  
Molecular Structures ◽  
Synthetic Methods ◽  
Complex Molecules ◽  
Bond Forming ◽  
Drug Candidates ◽  
Rapid Construction ◽  
Wide Range ◽  
Privileged Structures

Palladium-catalysed reactions have had a large impact on synthetic organic chemistry and have found many applications in target-oriented synthesis. Their widespread use in organic synthesis is due to the mild conditions associated with the reactions together with their tolerance of a wide range of functional groups. Moreover, these types of reactions allow the rapid construction of complex molecules through multiple bond-forming reactions in a single step, the so-called tandem processes. Pd-catalysed reactions have been applied to the synthesis of a large number of natural products and bioactive compounds, some of them of complex molecular structures. This review article aims to present an overview of the most important Pd-catalysed reactions employed in the synthesis and transformations of quinolin-2(1H)-ones and quinolin-4(1H)-ones. These compounds are widely recognized by their diverse bioactivity, being privileged structures in medicinal chemistry and useful structural moieties for the development of new drug candidates. Furthermore, they hold significant interest due to their host–guest chemistry; applications in chemical, biochemical and environmental analyses and use in the development of new synthetic methods. In some cases, the quinolone formation step cannot be ascribed to a claimed Pd-catalysed reaction but this reaction is crucial to get the appropriate substrate for cyclization into the quinolone. Herein we present and discuss different economical, efficient and selective synthetic strategies to access quinolone-type compounds.

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