An electrostatically enhanced phenol as a simple and competent bifunctional organocatalyst for the atom‐economical conversion of epoxides to cyclic carbonates under environmentally benign conditions is described. Incorporating a positively charged center into phenols through a modular one‐step synthesis results in a bifunctional system with enhanced acidity and reactivity, capable of epoxide activation, a halide nucleophilic ring‐opening process, and CO2 incorporation in a synergistic fashion. A rational survey of the efficiency of different positively charged phenols and the influence of different parameters, such as temperature, catalyst loading, and the nature of the nucleophile, on catalytic activity was conducted. In addition, the time‐dependent conversion of epoxide into the corresponding cyclic carbonate was further explored by FTIR‐ATR and 1H NMR spectroscopy. This bifunctional catalytic platform is among one of the mildest and most efficient metal‐free systems that is capable of converting a variety of epoxides into cyclic carbonates under virtually ambient conditions. The 1H NMR titration experiment validated the bifunctional catalytic mechanism wherein both the epoxide activation and the nucleophilic ring‐opening process occur in concert en route to carbon dioxide fixation.

Herein we describe an unprecedented isocyanide-based cycloaddition of alkyl and aryl isocyanides with (Z)-2-(2-hydroxy-2-alkylvinyl)quinoline-3-carbaldehydes. On the basis of DFT calculations a mechanism is proposed.

An aminopyridinium ionic liquid is presented as a green, tunable, and active metal‐free one‐component catalytic system for the atom‐efficient transformation of oxiranes and CO2 to cyclic carbonates. Inclusion of a positively charged moiety into aminopyridines, through a simple single‐step synthesis, provides a one‐component ionic liquid catalytic system with superior activity; effective in ring opening of epoxide, CO2 inclusion, and stabilization of oxoanionic intermediates. An efficiency assessment of a variety of positively charged aminopyridines was pursued, and the impact of temperature, catalyst loading, and the kind of nucleophile on the catalytic performance was also investigated. Under solvent‐free conditions, this bifunctional organocatalytic system was used for the preparation of 18 examples of cyclic carbonates from a broad range of alkyl‐ and aryl‐substituted oxiranes and CO2, where up to 98 % yield and high selectivity were achieved. DFT calculations validated a mechanism in which nucleophilic ring‐opening and CO2 inclusion occur simultaneously towards cyclic carbonate formation.

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In this project, a moderately efficient approach to multisubstituted N-(isoquinolin-1-yl)sulfonamide derivatives was illustrated, utilizing ortho-alkynylbenzaldoximes and zwitterionic ketenimine salts in a tandem reaction catalyzed by silver oxide. The oxophilicity of Ag 2 O, along with its nature as Lewis acid, pave the way for a smooth [3 + 2] cycloaddition between isoquinoline Noxides and ketenimine species, which is a key step in this reaction. DFT calculation suggests that 1,3-dipolar cycloaddition of nitrone and ketenimine proceeds through a selective stepwise mechanism.