Stability of electron deficient activated nitronates under neutral and Lewis acid catalyzed conditions. Facile nitronate cycloaddition reactions to the magnesium alkoxides of allylic alcohols leading to isoxazolidines and isoxazolines

✍ Scribed by Shuji Kanemasa; Shinsuke Kaga; Eiji Wada

• Book ID: 104260129
• Publisher: Elsevier Science
• Year: 1998
• Tongue: French
• Weight: 292 KB
• Volume: 39
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/s0040-4039(98)01902-9

✦ Synopsis

N-Methoxy-N-[bis(methoxycarbonyl)methylene]amine N-oxide and N-methoxy-N-(methoxycarbonylmethylene)amine N-oxide as electron-deficient activated nitronates, show an exceptionally high reactivity to the magnesium alkoxides of allylic alcohols. Isoxazolidines or isoxazolines are formed as cycloadducts, depending upon the substitution pattern of the allylic alcohols. When the latter C-monosubstituted nitronate is treated with a catalytic amount of boron trifluoride etherate, the corresponding nitrile oxide is smoothly generated through [~-elimination of methanol.