Base-Mediated Tandem [3 + 2] Cycloaddition/Ring Openning Reaction of Arylhydrazonoyl Chlorides with Arylnitroso Compounds for Synthesis of Substituted Diazene Oxides

A base-mediated tandem [3 + 2] cycloaddition/ring opening reaction of nitrilimines generated from arylhydrazonoyl chlorides with arylnitroso compounds has been developed. This protocol provides a novel and rapid approach for the synthesis of substituted azoxy compounds under mild conditions with moderate to good yields and a broad substrate scope.

Recent Advances in the Generation of Nitrilium Betaine 1,3-Dipoles

Nitrilium betaine 1,3-dipoles are ubiquitous reagents in organic chemistry, with applications ranging from natural product synthesis to materials science. Given the high reactivity of these zwitterionic motifs, they are invariably generated in situ from a suitable precursor, prior to use. This short review summarises the recent progress in the development of modern approaches towards the formation of these 1,3-dipoles, and their applications within a diverse range of fields.

1 Introduction

2 Nitrile Ylides

2.1 2H-Azirine Rearrangement

2.2 Addition of Nitriles to Carbenes

3 Nitrile Imines

3.1 2,5-Tetrazole Thermolysis

3.2 2,5-Tetrazole Photolysis

3.3 Diaryl Sydnone Photolysis

4 Nitrile Oxides

4.1 Hypervalent Iodine

4.2 The Nitroso Radical

4.3 Green Chemistry Approaches

4.4 Other Approaches

5 Conclusions