Synthesis of Heterocycles from Donor-Acceptor Cyclopropanes: A Five-Year Recap

Abstract

The utility of donor-acceptor cyclopropanes (DACs) for the construction of heterocycles is discussed here. In addition to (3+2), (3+3) and (4+3) cycloaddition pathways, nucleophilic ring-opening reactions, intramolecular transformations and cycloisomerizations in presence of suitable catalysts pave way for the generation of heterocycles from DACs. Mild reactions conditions employed and the variety of starting materials that can be used as reaction partners makes the DAC route for heterocycle synthesis attractive. The literature from 2018-2023 is categorized as below. 1 Introduction 2 Synthesis of Nitrogen heterocycles 2.1 By annulations with anthranils and azadienes 2.2 By nucleophilic attack of anilines and hydrazones 2.3 By reaction with ureas and thioureas 2.4 By annulation reactions using azomethine imine 2.5 By reaction with other N-heterocycles 2.6 By other transformations 3 Synthesis of Oxygen heterocycles 3.1 By intramolecular transformations 3.2 By intermolecular reactions 4 Synthesis of Sulphur/Selenium heterocycles 4.1 By reaction with thiocarbonyl substrates 4.2 By reaction with thio/selenocyanates and thiosulfonate salts 5 Synthesis of N-S/O heterocycles 6 Conclusions

Synthesis of Fully Substituted Pyrazoles with a Dicyanomethyl Group via DBU/Lewis Acid-Mediated Annulation of D–A Cyclopropanes with Arylhydrazines

“…On the contrary, cyclopropane chemistry has attracted a great deal of attention . Among them, various multifunctional D–A cyclopropanes were widely used to construct all kinds of acyclic, carbocyclic, and heterocyclic compounds because an extra aroyl group or nitro group not only affects the electron density of C–C bonds of cyclopropane leading to selective cleavage of the bonds of cyclopropane but also could participate in the annulation reactions .…”

Electrochemical 1,3-Alkyloxylimidation of Arylcyclopropane Radical Cations: Four-Component Access to Imide Derivatives

“…Cyclopropane is a synthetically attractive and versatile C3 building block that has been widely applied in total synthesis and drug discovery . Analyzing their structure, cyclopropanes are willing to undergo a ring-opening reaction owing to their inherent small ring strain and the inefficient orbital overlap of the C–C σ-bond.…”