Spiroheterocycles via Regioselective Cycloaddition Reactions of Nitrile Oxides with 5-Methylene-1H-pyrrol-2(5H)-ones

Nicola J. Beattie; Craig L. Francis; Andris J. Liepa; G. Paul Savage

doi:10.1071/CH09479

RESEARCH ARTICLE

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Spiroheterocycles via Regioselective Cycloaddition Reactions of Nitrile Oxides with 5-Methylene-1H-pyrrol-2(5H)-ones

Nicola J. Beattie ^A , Craig L. Francis ^A , Andris J. Liepa ^A and G. Paul Savage ^A ^B

+ Author Affiliations

- Author Affiliations

^A CSIRO Molecular and Health Technologies, Private Bag 10, Clayton South MDC, Vic. 3169, Australia.

^B Corresponding author. Email: paul.savage@csiro.au

Australian Journal of Chemistry 63(3) 445-451 https://doi.org/10.1071/CH09479
Submitted: 9 September 2009 Accepted: 21 October 2009 Published: 26 March 2010

Abstract

Substituted 5-methylene-1H-pyrrol-2(5H)-ones underwent a 1,3-dipolar cycloaddition reaction with nitrile oxides to give the corresponding spiro heterocycles. Critical to this reaction was the development of a biphasic system for base-induced dehydrohalogenation of hydroximoyl chlorides, to give nitrile oxides, in the presence of a base-sensitive dipolarophile. A substituted N-tolyl 5-methylene-1H-pyrrol-2(5H)-one exhibited atropisomerism, which in turn led to a 4:1 facial selectivity during cycloaddition.

Acknowledgement

We thank Dr Craig Forsyth (Monash University) for crystallography and Dr Roger Mulder (CSIRO) for assistance with NMR spectroscopy.

References

Spiroheterocycles via Regioselective Cycloaddition Reactions of Nitrile Oxides with 5-Methylene-1H-pyrrol-2(5H)-ones

Abstract

Acknowledgement

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