Synthesis of Complex Dihydroisoquinolin Derivatives via Cobalt‐Electrocatalyzed C−H Activation

The preservation of scarce rare earth metals, such as palladium, rhodium, iridium, and others, poses a significant challenge for humanity due to their limited availability. These rare earth metals might be replaced by earth‐abundant 3d‐transition metals such as cobalt, manganese, iron, nickel, copper, etc. Isoquinolines have acquired an important position in synthetic organic chemistry as well as medicinal chemistry. They manifest in a diverse range of natural and synthetic molecules, serving as pivotal synthons for the synthesis of numerous bioactive compounds with notable medicinal significance. Numerous reports on the synthesis of isoquinoline derivatives via transition metal catalysis have been published worldwide. In this review, we summarize recent approaches for synthesizing various isoquinoline derivatives using 3d‐transition‐metal catalysts since 2020. The review has been divided into different 3d‐transition‐metal‐based catalysis. We expect that this review will bring a better overview of the present status of the significant progress made in the 3d‐transition‐metal‐based synthesis of isoquinolines and persuade more advancements and research in this area in the near future.

Section: Cobalt Catalysismentioning

confidence: 99%

“…In 2023, Huang and Dong [51] developed a Co(II)‐electrocatalyzed annulation of amides 54 and 55 alkenes to afford various dihydroisoquinoline derivatives 56 utilizing an undivided cell setup (Scheme 22). The amides 54 were reacted with alkenes 55 using Co(acac) 2 (20 mol %), NaOPiv (2 equiv.…”

Section: Metal‐catalyzed Synthesis Of Isoquinolinesmentioning

confidence: 99%

Recent Advances in the 3 d‐Transition‐Metal‐Catalyzed Synthesis of Isoquinolines and its Derivatives

Maikhuri,

Rawat,

Rawat

2023

“…In the last few years, scientists have made numerous efforts to develop unconventional electro-organic processes for accomplishing various pharmaceutically essential and biologically active heterocyclic motifs. [1][2][3][4] Remarkably, the electrochemical technique serves electric current as the source of electrons, which could drive several chemical reactions. Thus, such a process would be devoid of the use of toxic/oxidizing/ reducing reagents and reduce waste generation.…”

mentioning

confidence: 99%

Electrochemical Annulation of ortho‐Alkynylbiphenyls to Fused Sulfenyl Phenanthrenes and Spiro Cyclohexenone Indenes

Balajirao Dapkekar,

Naveen,

Satyanarayana

2023

Here, we present an electrochemically induced synthesis of 9‐sulfenylarylphenanthrenes and 3’‐sulfenylarylspiro‐cyclohexa[4.5]trienones starting from o‐alkynylbiphenyls and diaryl disulfides. This method was accomplished through constant current electrolysis of 10 mA in an undivided cell setup by utilizing CH3CN as a solvent and LiClO4 as an electrolyte at room temperature. Notably, the present strategy enabled the formation of sulfenylphenanthrenes and sulfenyl spiro cyclohexa[4.5]trienones in 70%–95% yield. Scale‐up synthesis, mechanistic studies, and cyclic voltammetry have also been carried out.

Ligand Promoted and Cobalt Catalyzed Electrochemical C−H Annulation of Arylphosphinamide and Alkyne

Zhang

et al. 2023

A cobaltaelectro-catalyzed dehydrogenative [4 + 2] annulation of arylphosphinamides with alkynes was proposed in the present study to selectively construct a range of cyclic phosphinamide derivatives. Picolinic acid acted as a ligand to promote this transformation. A total of 38 examples demonstrated broad substrate scope, sufficient functional tolerance and excellent regioselectivity. Moreover, no additional oxidants and electrolytes were needed and it was possible to achieve gram scale synthesis, late-stage diversification and the removal of the directing group. Cyclic voltammetry and kinetic isotope experiments provided a better understanding to the reaction mechanism.