One of the active principles of Amanita muscaria, 5-aminomethyl-3-hydroxyisoxazole (I) has been synthesised from 3-bromo-5-methylisoxazole by way of 3-methoxyisoxazole-5-acetic acid (XIII), and from 3-methoxyisoxazole-5-carboxylic acid (XXa) by reduction of its amide with diborane. Analogues of (I) with methyl and ethyl substituents in the 4-position have been prepared similarly from 3-hydroxy-4,5-dimethylisoxazole
Cu(I)-catalyzed synthesis of spiro[isoquinoline-4,2'-[1,3]oxazin]-3-ones via ring expansion reactions of isoxazoles with 4-diazoisoquinolin-3-ones
作者:Minghui Qi、Muhammad Suleman、Jiale Fan、Ping Lu、Yanguang Wang
DOI:10.1016/j.tet.2022.133092
日期:2022.12
Herein, we report a copper(I)-catalyzed ring expansionreaction of isoxazoles with 4-diazoisoquinolin-3-ones, furnishing a series of densely substituted novel spiro[isoquinoline-4,2'- [1,3]oxazin]-3-ones in good to excellent yields. Broad substrate scope, readily available starting materials, cheap catalyst, mild reaction conditions and scalability are the prominent features of this methodology.