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1,4-Diazabicyclo[2.2.2]octane (DABCO) as an Efficient Reagent for the Synthesis of Isoxazole Derivatives from Primary Nitro Compounds and Dipolarophiles: The Role of the Base

Luca Cecchi, Francesco De Sarlo*, Fabrizio Machetti*

*Dipartimento di Chimica Organica U. Schiff, UniversitÓ di Firenze, Via della Lastruccia 13, 50019 Sesto Fiorentino - Firenze, Italy, Email: francesco.desarlounifi.it, fabrizio.machettiunifi.it

L. Cecchi, F. De Sarlo, F. Machetti, Eur. J. Org. Chem., 2006, 4852-4860.

DOI: 10.1002/ejoc.200600475 (free Supporting Information)


Abstract

The dehydration of primary nitro compounds can be performed by bases in the presence of dipolarophiles. Among the organic bases examined, DABCO gave the best results. The reaction is applicable to activated nitro compounds and to phenylnitromethane and affords isoxazoline derivatives in higher yields compared with those of other methods. The reaction, however, is not compatible with nitroalkanes.

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proposed mechanism



Key Words

1,3-dipolar cycloaddition, DABCO, Nitro Compounds, Isoxazolines, Isoxazoles


ID: J24-Y2006-3650