Hydroxylamine disubstituted alkynes

Scheme 10.9 Synthesis of 3,5-disubstituted isoxazoles from aldehydes, hydroxylamine, and terminal alkynes.

Efficient and regioselective iron-catalyzed aerobic oxidative reactions afforded 3,5-disubstituted isoxazoles 5 from homopropargylic alcohols 4, r-BuONO as the nitrogen source, and H2O under mild conditions (140L6298).A transition metal-free one-pot synthesis of 3,5-disubstituted isoxazoles used terminal alkynes by treatment with -BuLi, then aldehydes and iodine to afford intermediate a-alkynyl ketones 6 converted into isoxazoles 7 with hydroxylamine (14JOC2049). 

---