Nitrile oxide 1,3 dipolar cycloaddition is a simple and powerful coupling methodology. However, the self-dimerization of nitrile oxides has prevented the widespread use of this strategy for macromolecular coupling. By combining an in situ nitrile oxide generation with a highly reactive activated dipolarophile, we have overcome these obstacles and present a metal-free macromolecular coupling str...

Nitrile oxides were generated by the catalytic dehydrogenation of aromatic aldehyde oximes 2a-g with chloramine-T as oxidizing agent. The 1,3-dipolar cycloaddition of in situ generated nitrile oxides with ethyl oleate 1 produced a series of new ethyl 8-(3-aryl-4-octyl-4,5-dihydroisoxazol-5-yl)octanoate 3a-g in 6584% yield. Some of the synthesized cycloadducts have exhibited moderate to good ant...

An efficient protocol for the synthesis of a range of 1,2-benzisoxazoles using an improved 1,3-dipolar cycloaddition of nitrile oxides and benzyne is described. Key to the procedure is the in situ generation of the reactive nitrile oxide and benzyne reactants simultaneously.

An efficient synthesis of a range of 1,2-benzisoxazoles using an improved 1,3-dipolar cycloaddition of nitrile oxides and benzyne is described. Key to the procedure is the in situ generation of the reactive nitrile oxide and benzyne reaction partners mediated by TBAF. Reactions are complete within 30 s, giving the target products in good to excellent yield.

The [3+2] cycloadditions of N-methyl derivatives of unsaturated imides with various nitrile oxides to yield new bridged isoxazoline derivatives with potential biological activity is described.

The [3 + 2] and [3 + 3] cyclodimerisation processes of small nitrile oxides, XCNO (X = F, Cl, Br, CN, CH(3)) are investigated by ab initio coupled cluster theory at the CCSD, CCSD(T) and MR-AQCC levels for the first time. The favoured dimerisation process is a multi-step reaction to furoxans (1,2,5-oxadiazole-2-oxides) involving dinitrosoalkene-like intermediates with diradical character. The r...

Novel three-component heterocyclization involving gem-bromofluorocyclopropanes, nitrosyl tetrafluoroborate, and a molecule of the solvent (nitrile) yielding previously unknown fluorinated pyrimidine N-oxides is described. A two-step synthetic approach to 4-fluoropyrimidine N-oxides from alkenes under mild conditions is developed using this reaction. Mechanistic aspects of the heterocyclization ...

A series of carbapenems containing novel C-2 semisaturated heterocyclic substituents were synthesised by 1,3 dipolar cycloaddition reactions of nitrile oxides, nitrile imines and a nitrone to 2-vinylcarbapenem. The isoxazoline and isoxazolidine compounds showed potent antibacterial activity but moderate stability to human dehydropeptidase 1 (DHP-1). Stability to DHP-1 was improved by methyl sub...

Galactosides and lactosides bearing triazoles or isoxazoles, regiospecifically prepared by [1,3]-dipolar cycloadditions between alkynes, azides or nitrile oxides, provided specific galectin-1 and -3 inhibitors with potencies as low as 20 microM.