Valorization of Carbon Dioxide into Oxazolidinones by Reaction with Aziridines

The reduction of carbon dioxide has gained much attention due to increasing environmental concerns about global warming associated with carbon emissions from industrial effluents and public transport etc. In this regard, considerable attention has been devoted to the chemical conversion of carbon dioxide, and its incorporation into synthetic organic molecules under mild and “green” conditions. In recent years, significant effort has been dedicated to studying the fixation of carbon dioxide with aziridines to afford oxazolidinones, which is an environmental friendly and atom economical process. In this review, we discuss the efficiency of different catalytic systems, by comparing and analyzing each reaction parameter such as pressure, temperature, substrate scope and product selectivity

Role of temperature in [3+2]-cycloaddition of isoselenocyanates with oxiranes using BF<SUB>3</SUB>·Et<SUB>2</SUB>O

The [3+2]-cycloaddition reaction of isoselenocyanates with oxiranes using BF3·Et2O is temperature dependent affording generally either substituted 2-imino-1,3-oxaselenolanes (−5 °C) or 1,3-oxazolidinones (40 °C) in short reaction times with high yields

“On water”: efficient iron-catalyzed cycloaddition of aziridines with heterocumulenes

In suspension: The reaction of aziridines with heterocumulenes in the presence of Fe(NO3)3⋅9 H2O in aqueous suspension provides access to functionalized five-membered heterocycles in good to high yields. This protocol has a wide substrate scope, is simple, and uses a nontoxic and cheap catalyst

Synthesis of substituted pyrazoles from vinylhydrozones via bromoamination and hydroamination with 2,2,6,6-tetramethylpiperidine-1-oxyl and N-bromosuccinimide

The C-H oxidative amination of (Z)-1-allylidene-2-arylhydrazines with 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)/N-bromosuccinimide (NBS) provides highly substituted pyrazoles with 100 % regioselectivity in moderate to good yields. These protocols are effective at room temperature and offer a route for the construction of the target five membered heterocycles

Synthesis of Oxazolidinones by using Carbon Dioxide as a C1 Building Block and an Aluminium-Based Catalyst

Oxazolidinone synthesis through the coupling of carbon dioxide and aziridines was catalysed by an aluminium(salphen) complex at 50–100 °C and 1–10 bar pressure under solvent-free conditions. The process was applicable to a variety of substituted aziridines, giving products with high regioselectivity. It involved the use of a sustainable and reusable aluminium-based catalyst, used carbon dioxide as a C1 source and provided access to pharmaceutically important oxazolidinones as illustrated by a total synthesis of toloxatone. This protocol was scalable, and the catalyst could be recovered and reused. A catalytic cycle was proposed based on stereochemical, kinetic and Hammett studies

Efficient pyrrolidine catalyzed cycloaddition of aziridines with isothiocyanates, isoselenocyanates and carbon disulfide “on water”

The cycloaddition of aziridines with isothiocyanates, isoselenocyanates and carbon disulfide has been described using pyrrolidine as catalyst on water at moderate temperature. This protocol features the use of commercial amine as catalyst and water as solvent affording a potential route for the construction of five membered heterocycles in high yields

Expedient synthesis of tetrasubstituted pyrroles via a copper-catalyzed cascade inter-/intramolecular cyclization of 1,3-enynes carry a nitro group with amines

Various tetrasubstituted pyrroles/pyrazoles have been prepared from nitro-substituted 1,3-enynes with aromatic amines/hydrazines via a copper-catalyzed cascade aza-Michael addition, cyclization and aromatization at room temperature. This protocol is also effective for the synthesis of tetrasubstituted pyrazoles in high yields

A novel tandem sequence to pyrrole syntheses by 5-endo-digcyclization of 1,3-enynes with amines

The synthesis of pentasubstituted pyrroles has been described using molecular iodine from 1,3-enynes and amines via a sequential tandem aza-Michael addition, iodocyclization, and oxidative aromatization. The protocol is simple and efficient to afford the target products at ambient conditions

Enantiospecific Aluminum-Catalyzed (3+2) Cycloaddition of Unactivated Aziridines with Isothiocyanates

An Al­(salen)Cl efficiently catalyzed the enantiospecific (3+2) cycloaddition of unactivated chiral aziridines with isothiocyanates to furnish functionalized iminothiazolidines at room temperature with 94–99% ee. The use of an aluminum Lewis acid as the catalyst, high enantiomeric purities, mild reaction conditions, broad substrate scope, and the high atom economy are the significant practical features

Stereospecific Copper-Catalyzed Domino Ring Opening and sp³ C–H Functionalization of Activated Aziridines with <i>N</i>‑Alkylanilines

Copper efficiently catalyzed nucleophilic ring opening, sp³ C–H functionalization, and C–N bond formation in the presence of <i>tert</i>-butyl hydroperoxide to afford functionalized imidazolidines starting from <i>N</i>-sulfonylaziridines and <i>N</i>-alkylanilines. The products were obtained in high optical purities (95 → 99% ee) with excellent functional group tolerance