RECENT DEVELOPMENT OF THE CHEMISTRY OF 2-ISOXAZOLINES - FOCUSED ON ITS REGIOSELECTIVITY AND STEREOSELECTIVITY

2-Isoxazolines (4,5-dihydroisoxazoles) are recognized as useful intermediates in organic synthesis. The synthetic utilites of them are as follows : Firstly, they are readily prepared via an inter- or an intramolecular 1,3-dipolar cycloaddition ot nitrile oxides. Secondly, they can be converted into various important synthetic units such as beta-hydroxy ketones or gamma-amino alcohols. The isoxazoline strategy can be regarded as an aldol alternative strategy for construction of aliphatic and alicyclic compounds. In this review, recent development of the chemistry of 2-isoxazoline is described. I focus my attention to the following three topics : the stereo- and regiochemical course of the intermolecular 1,3-dipolar cycloaddition reaction of nitrile oxides, the stereochemical course of intramolecular 1.3-dipolar cycloaddition of nitrile oxides, and the stereoselective construction of side chains of 2-isoxazolines.