corresponding 5,5-disubstituted isoxazolidine as a single diastereomer in good yield. This reaction has been used as the key step in an asymmetric synthesis of the naturally occurring antibiotic, (-)-cispentacin. An asymmetric synthesis of 4-amino-pyrrolidine-3-carboxylic acid has also been carried out using the intramolecular nitrone cycloaddition as the stereocontrolling step.
使用三碳系链将分子内 1,3-偶极硝酮环加成到对映体纯的
乙烯酮二
硫代
乙醛上,得到相应的 5,5-二取代
异恶唑烷,作为单一的非对映异构体,收率良好。该反应已被用作天然抗生素 (-)-顺喷他星不对称合成的关键步骤。还使用分子内硝酮环加成作为立体控制步骤进行了 4-
氨基-
吡咯烷-3-
羧酸的不对称合成。