Dedicated to Alessandro Salomone, born on 10 May 2013
Abstract
Heterocyclic compounds are crucial starting reagents and intermediates, or they are
direct precursors of target chemicals and/or bio-pharmacological active compounds.
Today, they are used in the total synthesis of natural products, in drugs or herbicides,
and agrochemical preparation. Developing synthetic strategies targeting isoxazoles
is a recurrent aim in preparative chemistry. In particular, five-membered heterocycles
such as isoxazoles and isoxazolines are easily formed in a two steps or by a ‘one-pot’
procedure, by reacting aryl nitrile oxides with a variety of enolates of carbonyl
compounds (i.e., aldehydes, ketones, carboxylic acids), followed by aromatization.
Such a methodology was found to be selective and versatile allowing the preparation
of pharmacologically active isoxazoles in high yields.
1 Introduction
2 Preparation, Synthetic Applications, and Reactivity of 3-Aryl-5-hydroxy-2-isoxazolines
and 3-Arylisoxazoles
3 Synthesis of 5-Alkyl-3-aryl-5-hydroxy-2-isoxazolines and 5-Alkyl-3-arylisoxazoles
4 Synthesis and Reactivity of 3,4-Diaryl-5-hydroxy-2-isoxazolines and 3,4-Diarylisoxazoles
5 Synthesis and Reactivity of 3-Aryl-5-hydroxy-5-vinyl-2-isoxazolines and 3-Aryl-5-vinylisoxazoles
6 Synthesis of 3-Aryl-4-phenylisoxazole-5-carboxylic Acid
7 Conclusions
8 Experimental Methodologies
Key words
1,3-dipolar cycloaddition - lithium enolates - arylisoxazoles - 3-aryl-5-hydroxy-2-isoxazolines
- 3,4-diarylisoxazoles
