One-Pot Synthesis of Pyrrolo[3,4- a ]indolizine-1,3-diones through [3+2] Cycloaddition-Oxidation Reaction Catalyzed by Cu II Salt and O 2 as the Oxidant: Synthesis of Pyrrolo[3,4- a ]indolizine-1,3-diones

External oxidant-free oxidation/[3+2] cycloaddition/aromatization cascade: electrochemical synthesis of polycyclic N-heterocycles

The extent of the electrochemical oxidative [3+2] cycloaddition/aromatization cascade can be regulated with the assistance of redox mediators. Isoquinolinium salts as alternative azomethine ylide precursors afforded fully aromatized N-heterocycles.

Transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization reactions for the synthesis of annulated indolizines

A transition-metal-free catalyzed [3+2] cycloadditions/oxidative aromatization three-component reactions for direct construction of annulated indolizines was reported.

Synthesis of Pyrrole via a Silver-Catalyzed 1,3-Dipolar Cycloaddition/Oxidative Dehydrogenative Aromatization Tandem Reaction

Pyrroles are an important group of heterocyclic compounds with a wide range of interesting properties, which have resulted in numerous applications in a variety of fields. Despite the importance of these compounds, there have been few reports in the literature pertaining to the synthesis of pyrroles from simple alkenes using a one-pot sequential 1,3-dipolar cycloaddition/aromatization reaction sequence. Herein, we report the development of a benzoyl peroxide-mediated oxidative dehydrogenative aromatization reaction for the construction of pyrroles. We subsequently developed a one-pot tandem reaction that combined this new method with a well-defined silver-catalyzed 1,3-dipolar cycloaddition reaction, thereby providing a practical method for the synthesis of multisubstituted pyrroles from easy available alkenes. The mechanism of this oxidative dehydrogenative aromatization reaction was also examined in detail.

Synthesis of pyrrolo[2,1,5-cd]indolizines through dehydrogenative Heck annelation of indolizines with diaryl acetylenes using dioxygen as an oxidant

A dehydrogenative Heck annelation reaction of indolizine with diaryl acetylene via dual C-H bond cleavage was developed. Oxygen gas was employed as a clean oxidant in this catalysis under base-free conditions. Diarylpyrrolo[2,1,5-cd]indolizines were synthesized with high atom economy. In addition, kinetic isotope experiments provided evidence for C-H bond metalation of the 5-position of the indolizine as the rate-limiting step.

One-pot synthesis of indolizine via 1,3-dipolar cycloaddition using a sub-equivalent amount of K2Cr2O7 as an efficient oxidant under base free conditions

X = Cl or Br; EWG₁, EWG₂ = electron withdrow group, one-pot reaction, 29 examples, yields from moderate to high, gram scale-up potential confirmed.

Copper(ii) bromide-catalyzed intramolecular decarboxylative functionalization to form a C(sp3)–O bond for the synthesis of furo[3,2-c]coumarins

Copper(ii) bromide-catalyzed intramolecular decarboxylative functionalization to form a C(sp³)–O bond has been developed.

Copper(II)-catalyzed indolizines formation followed by dehydrogenative functionalization cascade to synthesize 1-bromoindolizines

A one-pot, three-component cascade reaction between pyridine, α-acylmethylbromide, and maleic anhydride leading to direct access of 1-bromoindolizines in high yields has been developed. This protocol is accomplished via a reaction sequence of 1,3-dipolar cycloaddition of the pyridinium ylide with maleic anhydride, oxidative decarboxylation of the primary cycloadduct, and dehydrogenative bromination of the resulting 1-unsubstituted indolizine. Copper chloride was used as a catalyst and oxygen as the terminal oxidant. This reaction represents the first example of transition-metal-catalyzed direct dehydrogenative bromination of indolizine at the C-1 position. Moreover, the obtained 1-bromoindolizines can be transformed to other 1-substituted indolizines such as 1-arylindolizines via a simple reaction process.

Copper(ii)-catalyzed cleavage of carbon–carbon triple bond to synthesize 1,2,3-triesterindolizines

An efficient Cu(ii)-catalyzed carbon–carbon triple bond cleavage protocol for the synthesis of 1,2,3-triesterindolizines via the reaction of pyridines with butynedioates has been developed.