The cycloaddition of azomethine ylides to [60]fullerene (C60) has been studied in ortho-dichlorobenzene (o-DCB) by evaluating the impact an ionic liquid (IL) additive. solvent effect addressed activation parameters and boosting microwave (MW) induced dielectric heating. IL additive plays a twofold role stabilizing dipolar ylide intermediate favoring retro-cycloaddition at high temperature regim...

The 1,3-dipolar cycloaddition of azides and activated alkynes has been used for site-selective labeling of biomolecules in vitro and in vivo. While copper catalysis has been widely employed to activate terminal alkynes for [3 + 2] cycloaddition, this method, often termed "click chemistry", is currently incompatible with living systems because of the toxicity of the metal. We recently reported a...

The 1,3-dipolar cycloaddition reaction (1,3-DC) has offered the opportunity to produce a wide range of heterocyclic compounds [1,2]. These compounds were used to prepare new molecules of crucial importance for both pharmaceutics and industry sector [3]. The application of 1,3-DC reactions in natural product synthesis is heavily dependent upon an understanding of the regioselectivity and chemios...

The cycloaddition of azides to alkynes is one of the most important synthetic routes to 1H-[1,2,3]-triazoles. Here a novel regiospecific copper(I)-catalyzed 1,3-dipolar cycloaddition of terminal alkynes to azides on solid-phase is reported. Primary, secondary, and tertiary alkyl azides, aryl azides, and an azido sugar were used successfully in the copper(I)-catalyzed cycloaddition producing div...

The 1,3-dipolar cycloaddition of azomethine ylides bearing the biologically active 1,4-dihydropiridine ring to C(60) was investigated by means of quantum mechanical calculations at the semiempirical AM1 and DFT (B3LYP/6-31G) methods. The presence of two chiral centers and one chiral axis in the resulting fulleropyrrolidines leads to four possible [6,6] cycloaddition products. Formation of atrop...

Azlactones participate in stereoselective reactions with electron-deficient alkenes and N-sulfonyl aldimines to give products of 1,3-dipolar cycloaddition and Mannich addition reactions, respectively. Both of these reactions proceed with good to excellent diastereo- and enantioselectivity using a single class of gold catalysts, namely C(2)-symmetric bis(phosphinegold(I) carboxylate) complexes. ...

The 1,3-dipolar cycloaddition of acyclic 2-diazo-1,3-dicarbonyl compounds (DDC) and thioketones preferably occurs with Z,E-conformers and leads to the formation of transient thiocarbonyl ylides in two stages. The thermodynamically favorable further transformation of C=S ylides bearing at least one acyl group is identified as the 1,5-electrocyclization into 1,3-oxathioles. However, in the case o...

The cycloaddition of 4-methoxycarbonyl-2(1H)-pyridones to silyloxydienes gave isoquinolone derivatives in reasonable yields. Furthermore, the cycloaddition of 6-methoxycarbonyl-2(1H)-pyridones to 2,3-dimethyl-1,3-butadiene produced cycloadducts (isoquinolone and quinolone derivatives) and double cycloadducts (phenanthridone derivatives). The activation energies using Gaussian 98 with RHF/3-21G ...

The scope of the [4 + 2] cycloaddition reactions of substituted 1,2,3-triazines, bearing noncomplementary substitution with electron-withdrawing groups at C4 and/or C6, is described. The studies define key electronic and steric effects of substituents impacting the reactivity, mode (C4/N1 vs C5/N2), and regioselectivity of the cycloaddition reactions of 1,2,3-triazines with amidines, enamines, ...