The bioorthogonal chemical reporter strategy is emerging as a versatile method for the labeling of biomolecules, such as nucleic acids, lipids, carbohydrates, and proteins. In this approach, an abiotic chemical functionality (reporter) is incorporated into a target biomolecule and can then react with a complementary bioorthogonal functional group linked to one of a diverse set of probes. The az...

In this work, three possible mechanisms, including mechanisms A and B associated with the stereoselective [2 + 2] cycloaddition product and mechanism C associated with the [2 + 2 + 2] cycloaddition product, have been investigated for N-heterocyclic carbenes (NHCs) catalyzed cycloadditions of ketenes with isothiocyanates by using density functional theory (DFT). Our calculated results suggest th...

Natural products and their signature fragments are an enduring resource for identifying biological modulators. A number of biologically active alkaloids, such as strychnofoline and isorhynchophylline (Fig. 1), feature spiroindolizidine oxindoles. This fragment is considered ‘privileged’ for potential therapeutic investigation and there is much interest in developing expedient synthesis of such ...

the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reaction of azomethine ylides, derived from isatin, with electron-deficient dipolarophilewas described. the process occurs at room temperature in aqueous ethanol as a green solvent and in the presence of a bidendatebis(imine)–cu(...

Nitrile Oxide−Dehydroalanine Cycloaddition is a bioconjugation strategy between dehydroalanine-containing proteins and nitrile oxides, remarkably, in fully aqueous-buffered systems without an additional catalyst. This novel method of chemical protein modification forms isoxazoline ring enhancing the diversity function structure. The 1,3-dipolar cycloaddition reaction adds fluorescent label to f...

Key words (±)-talatisamine - Diels–Alder reaction [2+2] photo-cycloaddition Lemieux–Johnson oxidation retro-aldol–aldol Wagner–Meerwein rearrangement aza-Prins

Abstract Metal-catalyzed [2+2+2] cycloaddition is a powerful tool that allows rapid construction of functionalized 6-membered carbo- and heterocycles in single step through an atom-economical process with high functional group tolerance. The reaction usually regio- chemoselective although selectivity issues can still be challenging for intermolecular reactions involving the cross-[2+2+2] two or...

This review covers the application of cycloaddition reactions in forming the boron-containing compounds such as symmetric star-shaped boron-enriched dendritic molecules, nano-structured boron materials and aromatic boronic esters. The resulting boron compounds are potentially important reagents for both materials science and medical applications such as in boron neutron capture therapy (BNCT) i...

The synthesis of C3-carbocyclic spirooxindoles was realized by way of an intramolecular [2 + 2] cycloaddition reaction between a vinylidene indolin-2-one and an alkyne. The cycloaddition reaction occurs selectively with the distal double bond of the allene, is tolerant of a phenyl and trimethylsilyl group on the terminus of the alkyne, and can be used to access bicyclo[4.2.0]octadienes and bicy...

Click chemistry has become a ubiquitous chemical tool with applications in nearly all areas of modern chemistry, including drug discovery, bioconjugation, and nanoscience. Radiochemistry is no exception, as the canonical Cu(I)-catalyzed azide-alkyne cycloaddition, strain-promoted azide-alkyne cycloaddition, inverse electron demand Diels-Alder reaction, and other types of bioorthogonal click lig...