Recent Advances in Transition-Metal-Catalyzed (4+3)-Cycloadditions

Synthesis ◽  
2020 ◽  
Vol 52 (17) ◽  
pp. 2427-2449 ◽  
Author(s):  
Mark Lautens ◽  
Heather Lam

A (4+3)-cycloaddition combines a four-atom synthon and three-atom synthon to form seven-membered rings. In the past decade, many improvements have been made to this class of cycloaddition, including excellent diastereo- and enantioselectivities, both intra- and intermolecularly. Through the strategic use of transition-metal catalysts, acids, bases, and organocatalysts, it is possible to perform the cycloaddition on a variety of substrates, generating novel seven-membered rings. With these advances, (4+3)-cycloaddition has also been applied to the synthesis of biologically relevant compounds and natural products. We exclude the cycloadditions of cyclic dienes such as furan, pyrrole, cyclohexadiene or cyclopentadiene as Chiu, Harmata, Mascareñas­ and others have recently published thorough reviews on that topic. We will however discuss the recent additions (2009–2020) to the literature for the (4+3)-cycloadditions involving other types of four-atom synthons.1 Introduction2 Rhodium2.1 Cyclopropanation/Cope Rearrangement2.2 C–H activation3 Gold, Silver4 Copper5 Palladium, Platinum, Iridium6 Dual-Activation7 Conclusion

Author(s):  
Chandrasekaran Sivaraj ◽  
Alagumalai Ramkumar ◽  
Nagesh Sankaran ◽  
THIRUMANAVELAN GANDHI

Phthalazinones and their higher congeners are commonly prevalent structural motifs that occur in natural products, bioactive molecules, and pharmaceuticals. In the past few decades transition metal-catalyzed reactions have received an...


Synthesis ◽  
2018 ◽  
Vol 50 (14) ◽  
pp. 2693-2706 ◽  
Author(s):  
Jamie Leitch ◽  
Christopher Frost

Anilines are a vital synthetic core of pharmaceuticals, agrochemicals, natural products and building blocks. Metal-catalyzed C–H functionalization has emerged as a powerful tool to derivatize biologically relevant molecules. To this end, the derivation of anilines via catalytic C–H functionalization has been the subject of important new synthetic methodology. This review focuses on the tactics used to allow regioselective C–H functionalization of anilines.1 Introduction2 ortho-Selective C–H Functionalization2.1 Palladium2.2 Rhodium2.3 Ruthenium2.4 Nickel3 meta-Selective C–H Functionalization4 para-Selective C–H Functionalization5 Conclusion


Author(s):  
Jianxiao Li ◽  
Dan He ◽  
Zidong Lin ◽  
Wanqing Wu ◽  
Huanfeng Jiang

During the past decades, alkynes chemistry has attracted considerable attention owing to their unique and idiographic nucleophilic and electrophilic properties in transition-metal-catalyzed chemical transformations. Among the various metal catalysts, palladium...


Synthesis ◽  
2021 ◽  
Author(s):  
Heather Lam ◽  
Mark Lautens ◽  
Xavier Abel-Snape ◽  
Martin F. Köllen

Abstract(4+3)-Annulations are incredibly versatile reactions which combine a 4-atom synthon and a 3-atom synthon to form both 7-membered carbocycles as well as heterocycles. We have previously reviewed transition-metal-catalyzed (4+3)-annulations. In this review, we will cover examples involving bases, NHCs, phosphines, Lewis and Brønsted acids as well as some rare examples of boronic acid catalysis and photocatalysis. In analogy to our previous review, we exclude annulations involving cyclic dienes like furan, pyrrole, cyclohexadiene or cyclopentadiene, as Chiu, Harmata, Fernándes and others have recently published reviews encompassing such substrates. We will however discuss the recent additions (2010–2020) to the literature on (4+3)-annulations involving other types of 4-atom-synthons.1 Introduction2 Bases3 Annulations Using N-Heterocyclic Carbenes3.1 N-Heterocyclic Carbenes (NHCs)3.2 N-Heterocyclic Carbenes and Base Dual-Activation4 Phosphines5 Acids5.1 Lewis Acids5.2 Brønsted Acids6 Boronic Acid Catalysis and Photocatalysis7 Conclusion


Synthesis ◽  
2017 ◽  
Vol 50 (01) ◽  
pp. 1-16 ◽  
Author(s):  
Santosh Mhaske ◽  
Ranjeet Dhokale

The plethora of transformations attainable by the transition-metal-catalyzed reactions of arynes has found immense contemporary interest in the scientific community. This review highlights the scope and importance of transition-metal-catalyzed aryne reactions in the field of synthetic organic chemistry reported to date. It covers transformations achieved by the combination of arynes and various transition metals, which provide a facile access to a biaryl motif, fused polycyclic aromatic compounds, different novel carbocycles, various heterocycles, and complex natural products.1 Introduction2 Insertion of Arynes3 Annulation of Arynes4 Cycloaddition of Arynes5 Multicomponent Reactions of Arynes6 Miscellaneous Reactions of Arynes7 Total Synthesis of Natural Products Using Arynes8 Conclusion


2012 ◽  
Vol 85 (3) ◽  
pp. 493-509 ◽  
Author(s):  
Yun-Chin Yang ◽  
David E. Bergbreiter

Organocatalysts have been extensively studied for the past few decades as alternatives to transition-metal catalysts. Immobilizing organocatalysts on polymer supports allows easy recovery and simple product purification after a reaction. Select examples of recent reports that describe the potential advantages of using soluble polymers to prepare soluble polymer-supported organocatalysts useful in organic synthesis are reviewed.


2021 ◽  
Vol 19 (37) ◽  
pp. 7949-7969
Author(s):  
Prasanjit Ghosh ◽  
Sajal Das

Indole and its congeners are ubiquitous nitrogen containing organic scaffolds found in a plethora of natural products. This review aims to highlight the transition-metal catalyzed C–H functionalization of N-alkoxycarbamoyl indoles.


Synthesis ◽  
2020 ◽  
Vol 52 (07) ◽  
pp. 993-1006 ◽  
Author(s):  
Guanghua Kuang ◽  
Guangyuan Liu ◽  
Xingxing Zhang ◽  
Naihao Lu ◽  
Yiyuan Peng ◽  
...  

The most recent advances in the construction of oxygen heterocycles by the directing-group-assisted transition-metal-catalyzed direct oxidative annulation of arenes with diverse alkynes are summarized in this review. More than 140 recent research papers and many closely related reviews are referenced in this paper. Nine different oxygen heterocycles frameworks are discussed. Several traditional transition-metal catalysts as well as some classical non-noble metals are utilized to promote the annulation. Three plausible controlling models are disclosed to clarify the excellent regioselectivity outcomes achieved in case of unsymmetrical alkyne substrates.1 Introduction2 Coumarins3 I socoumarins and Their Analogues4 2-Pyrones and Their Analogues5 Chromones and Chroman-4-ones6 Chromenes and Isochromenes7 Fused Polycyclic Oxygen Heteroaromatics8 Benzofurans, Dihydrobenzofurans, and Furans9 Phthalides and Benzofuranones10 Benzoxepines11 Conclusion


2017 ◽  
Vol 2017 ◽  
pp. 1-15 ◽  
Author(s):  
Joseph C. Sloop

Heterocyclic molecules incorporating fluorinated isoquinoline components are found in many medicinally and agriculturally important bioactive products as well as industrially impactful materials. Within the past decade, a variety of isoquinolinic ring assembly techniques has enabled the introduction of diverse fluorine-containing functionalities which can enhance potential bioactivity and industrial utility. This review examines recent noncatalyzed and transition metal catalyzed synthetic approaches to the assembly of isoquinoline derivatives that are ring-fluorinated and/or result in the incorporation of fluorine-containing functional groups. Specifically, efficient synthetic methods and regioselectivity in the incorporation of functional groups into isoquinoline ring systems are examined.


Molecules ◽  
2020 ◽  
Vol 25 (14) ◽  
pp. 3147 ◽  
Author(s):  
Mickael Choury ◽  
Alexandra Basilio Lopes ◽  
Gaëlle Blond ◽  
Mihaela Gulea

Medium-sized heterocycles (with 8 to 11 atoms) constitute important structural components of several biologically active natural compounds and represent promising scaffolds in medicinal chemistry. However, they are under-represented in the screening of chemical libraries as a consequence of being difficult to access. In particular, methods involving intramolecular bond formation are challenging due to unfavorable enthalpic and entropic factors, such as transannular interactions and conformational constraints. The present review focuses on the synthesis of medium-sized heterocycles by transition-metal-catalyzed intramolecular cyclization, which despite its drawbacks remains a straightforward and attractive synthesis strategy. The obtained heterocycles differ in their nature, number of heteroatoms, and ring size. The methods are classified according to the metal used (palladium, copper, gold, silver), then subdivided according to the type of bond formed, namely carbon–carbon or carbon–heteroatom.


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