the catalytic highly regio-, diastereo-, and enantioselective synthesis of a small library of spiropyrrolizidineoxindolesvia a four-component 1,3-dipolar cycloaddition reactionof azomethineylides, 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(ii...

In the presence of 1 mol% of a copper(II) catalyst and air, a readily available N-acetyl-N-thioacylguanidine undergoes a one-pot benzylic oxidation–oxidative heterocyclization sequence to give the 3-amino5-acyl-1,2,4-thiadiazole core of polycarpathiamines A (2) and B (3) and thus facilitating the first synthesis of both natural products. This methodology offers a straightforward alternative to ...

The 1,3-dipolar cycloaddition of 3-nitro-2(1H)-quinolones with ester-stabilized azomethine ylides derived from sarcosine ester and various aromatic aldehydes has been investigated. structure stereochemistry cycloadducts were studied in detail by X-ray NMR spectroscopy methods.

An efficient synthesis of 1,3-diaryl-4-halo-1H-pyrazoles was achieved. The synthesis involves the [3 + 2] dipolar cycloaddition of 3-arylsydnones and 2-aryl-1,1-dihalo-1-alkenes. The process proceeds smoothly in moderate to excellent yields. 1,3-Diaryl-4-halo-1H-pyrazoles are found to be important intermediates that can easily be converted into 1,2,5-triaryl-substituted pyrazoles via Pd-catalyz...

Ferrocene derived P,S-heterodonor ligands were effectively used in AgOAc catalyzed asymmetric cycloaddition of azomethine ylides. The roles of planar chirality and electronic properties of the phosphorous substituents have been examined, and up to 93% ee was obtained. 2007 Elsevier Ltd. All rights reserved. The 1,3-dipolar cycloaddition reaction has become a powerful synthetic tool, providing a...

A series of spiro[isoindole-1,5-isoxazolidin]-3(2H)-ones has been synthesized by 1,3-dipolar cycloaddition of N-benzylnitrone with isoindolin-3-methylene-1-ones. The regio- and stereoselectivity of the process have been rationalized by computational methods. The obtained compounds show cytotoxic properties and antiproliferative activity in the range of 9-22 μM. Biological tests suggest that the...

This work reports for the first time a straightforward solvent-free chemical procedure to gain access to Δ-1-pyrroline grafted onto multiwalled carbon nanotubes by the 1,3-dipolar cycloaddition of the mesoionic 4-methyl-2-phenyloxazol-5(4H)-one.

1,3-Dipolar cycloaddition reactions of azomethine ylides play an important role in the synthesis of highly substituted pyrollidines which are found in the structures of many important natural products and pharmaceuticals . Using this chemistry, four chiral centers can be created in a single step. The asymmetric version of this reaction has been tried both with achiral azomethine ylides and chir...

a series of 1,3-dipolar cycloaddition reactions are carried out using cyclodimers of simple nitrones and various dipolarophiles; substituted isoxazolidines are isolated and identified. it is proved that such cyclodimers, in solution, are in equilibrium with their corresponding nitrones and enamines. it is also concluded that aldocyclodimers are more potent than keto-cyclodimers in establishing ...