Four-Component Reaction for the Synthesis of Indolizines by Copper-Catalyzed Aerobic Oxidative Dehydrogenative Aromatization: Four-Component Reaction for the Synthesis of Indolizines by Copper-Catalyzed Aerobic Oxidative Dehydrogenative Aromatization

Synthesis of Ester-Substituted Indolizines from 2-Propargyloxypyridines and 1,3-Dicarbonyls

Two new complementary Au(I)-catalyzed methods for the preparation of ester-substituted indolizines from easily accessible 2-propargyloxypyridines and either acetoacetates or dimethyl malonate are reported. These reactions tolerate a wide range of functionality, allowing for diversification at three distinct positions of the product (R, R¹, R²). For electron-poor substrates, the highest yields are observed upon reaction with acetoacetates, while neutral and electron-rich substrates give higher yields upon treatment with dimethyl malonate.

Electro-Oxidative sp3 C-H Bond Functionalization and Annulation Cascade: Synthesis of Novel Heterocyclic Substituted Indolizines

Indolizine derivatives are prevalent in many synthetic intermediates, pharmaceuticals, and organic materials. Herein, we report a novel electro-oxidative cascade cyclization reaction that uses electricity as the primary energy input to promote the reaction, leading to a series of heterocyclic substituted indolizine derivatives under exogenous-oxidant-free conditions. It is noteworthy that this electrochemical method provides a novel strategy for generating heterocyclic diversity of quinazolinones and quinolines on indolizines. In addition, the sole byproduct in the reaction was molecular hydrogen.

The regioselective annulation of N-methylpyridinium ylides with alkenes enabled by palladium catalysis: access to 3-unsubstituted indolizine derivatives

The first catalytic protocol for the regioselective [3 + 2] annulation of N-methyl pyridinium ylides with alkenes to establish various valuable 3-unsubstituted indolizine derivatives is accomplished via palladium catalysis at the unactivated position.

Au(I)-Catalyzed Synthesis of Trisubstituted Indolizines from 2-Propargyloxypyridines and Methyl Ketones

A new Au(I)-catalyzed method for the preparation of trisubstituted indolizines from easily accessible 2-propargyloxy-pyridines is reported. The reaction tolerates a wide range of functionality, allowing for diversity to be introduced in four distinct regions of the product (R, R¹, R², and Ar). The proposed mechanism proceeds via enol addition to an allenamide intermediate and explains the observed increase in yields when electron poor methyl ketones are utilized.

Indolizine quaternary ammonium salt inhibitors, part III: insights into the highly effective low-toxicity acid corrosion inhibitor – synthesis and protection performance

Three indolizine derivatives (Di-BQC, QM-DiBQC, PyM-DiBQC) were prepared facilely in high yield via 1,3-dipolar cycloaddition. These compounds exhibit good inhibition for steel in concentrated acid without the synergism of propargyl alcohol (PA).

Indolizine quaternary ammonium salt inhibitors part II: a reinvestigation of an old-fashioned strong acid corrosion inhibitor phenacyl quinolinium bromide and its indolizine derivative

Anti-corrosion inhibition was dramatically improved by transforming heterocyclic ammonium inhibitors into their dimer indolizine derivatives.

Indium(III)-catalyzed Aza-Conia-Ene Reaction for the Synthesis of Indolizines

A new indium(III)-catalyzed reaction for the synthesis of a series of indolizine scaffolds has been developed. This methodology was highly efficient, allowing a low catalyst loading of 2 mol % (down to 0.5 mol %) and rendering the products in high yields through a 5-exo-dig aza-Conia-ene reaction. Furthermore, the possibility of incorporating an electrophile into the generated pyrrolidone ring in a one-pot synergistic fashion was demonstrated. Finally, based on experimental observations, a mechanism proposal was outlined.

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.

Application of primary halogenated hydrocarbons for the synthesis of 3-aryl and 3-alkyl indolizines

A transition-metal-free synthetic route to 3-aryl and 3-alkyl indolizines from electron-deficient alkenes, pyridines and primary halogenated hydrocarbons is reported for the first time using a tandem reaction.