Science of Synthesis

Collier, S. J., Science of Synthesis, (2007) 33, 498.

An obvious disconnection of the N-alk-1-enylhydroxylamine unit reveals an enolizable ketone or aldehyde and a hydroxylamine derivative. However, the synthetic reaction is often complicated by the formation of isomeric side products. Clearly oximes are readily formed by this reaction sequence, but if the nitrogen atom of the hydroxylamine unit is substituted or if there is sufficient conjugative stabilization present, N-alk-1-enylhydroxylamines can be formed. With N-substituted hydroxylamines, condensation with aldehydes often gives nitrones.[‌29‌,‌30‌] In some cases both N-alk-1-enylhydroxylamines ‌16‌ and nitrones ‌17‌ are formed in the condensation, and undergo a 1,3-dipolar-cycloaddition reaction with one another to provide isoxazolidines ‌18‌ (‌Scheme 7‌).[‌29‌,‌30‌] Furthermore these oxazolidines can be in thermal equilibrium with the N-alk-1-enylhydroxylamines, undergoing retrocycloaddition upon heating (only the N-alk-1-enylhydroxylamine is observed by NMR; the equilibrium concentration of the nitrone is thought to be too low for detection). Upon cooling, the isoxazolidine is re-formed.[‌29‌,‌30‌]

‌Meeeee 8‌ Meeeeeeeee eeeeeee M-8-Meeeeeeeeeeeeeeeeeeee, Meeeeeee, eee Meeeeeeeeeeeee[‌88‌]

Meeeeee eeeee eeeeeeeeeeeee, M-eee-8-eeeeeeeeeeeeeeeeee ‌88‌ eee ee eeeeee eeeeeee eee eeeeee eeeeeeeeeeee ee e eeeeeeeeeeeee eeee e eeeeeeee eeeee (‌Meeeee 8‌). Me eeee eeeee, eeeeee ee M-eee-8-eeeeeeeeeeeeeeeee eee ee eeeeee eeee eeeeee eeeeeee eee eeeeeeeeeeeee, eeeeeeeee ee eee eeeeeeeeee eeeeeeee. Mee eeeeeeee ee eeee eeeeee eee eeeeeeeeeeeee, eeeeeee eee eeee eeeeeeee ee eee eeeeeee ee eeee eeeee ee eee eeeee.[‌88‌]

Meeeeeeee eeee eeeee ee eeeee eeee eeeeeeeee, eee eeeeeee, eeeeeee (eeeeeeeeeeeeeeee)eeeeeeee[‌88‌] ee 8-(eeeeeeeeeeeeeeee)eeeee-8-eee,[‌8‌,‌8‌,‌88‌] eee eeee ee eeee ee eee eeeeeeeeeeee eeeeeeee ee eeee ee M-eeeeeeeeeeeeeeeeee.[‌88‌] Me eee eeee ee 8-(eeeeeeeeeeeeeeee)eeeee-8-eee,[‌8‌,‌88‌] ee M-(eee-8-eeee)eeeeeeeeeeeee eee ee eeeeeeee eeeeeee eeeeeeeee eeee eeeeeeeeeeeeeeeeeee, eee eee eeeeeeeeeeeee 8-eeeeeeeee ee eeeeeeeeeeeee eeeeeeeeeee eeee eeee eee eeeeeeee eeeeeeee.[‌88‌] Meeeeeee ee eee 8-(eeeeeeeeeeeeeeee)eeeee-8-eeee eeee M-eeeeeeeeeeeeeeeeeee eeee eeeee eeeeeeee.[‌88‌] Meeeeeeeeeeeeeeeeeeee eee ee eeeeeeee eeeeeee eee eeeeeeeee ee 8-eee-8-eeeeeeeeeeeeeeeeeeee eeee M-eeeeeee-8-eeeeeeeeeeeeeeeeee ee M-eeeeeeeeeeeeeeee (‌Meeeee 8‌).[‌88‌]

‌Meeeee 8‌ M-Mee-8-eeeeeeeeeeeeeeeeee eeee Meeeeeee Meeeeeeee eee Meeeeeeeeeeeee[‌8‌,‌8‌,‌88‌–‌88‌]

‌Meeeeeeeeee 8‌

Mee eeeeeeeeeeee ee eeeeeeeeeeeeee eeee 8,8-eeeeeeeeee eeeeeeeee eeee ee β-eeeeeeeee[‌8‌] eee β-eee eeeeee[‌88‌] eee ee e eeee eeeee ee M-(8-eeeeee-8-eeee)eeeeeeeeeeeeee, eeeee eee eeeeeee ee eee eeeeeeeeeee eeeeeeeeeeeee ee eee eeeee eeee. Meee eeee ee eee eeeeee eeee eee eeeeeeeee eee eeeee eeeeeee ee eeeeeee eeeeeeeeeeee eee eee eee ee eeeeee eeeeeeee ee eeeeeeeee eeeeeee ee eee eeeeeeeeeeeee ee eee eeeeeee eeee eee eeeeeeee eeeeeee.[‌8‌] Me ee eeeeeeeeeee eeeeeee, eee eeeeeeeee ee eeeeee eeeeeeeee ‌88‌ eeee eeeeeeeeeeeee eee eeee ee eee eeeeeeeee eeeeeeee, e (8-eeeeeeeeeeeee)eeeeeeeee ‌88‌ eee e eeeeeeeeeeeee ‌88‌ eeeeeeeeee e M-8-(eeeeeeeeeeeee)eeeee eeeee (‌Meeeee 8‌). Mee eeeee ee eeeee eeeeeeee eee ee eeeeeeeeee ee eeeeeeee eee eeeeeeeeee eeeeeeee ee eee eeeeeeee eeeeee, eeee eeeeee eeeeeeeeee eeeeeeeee eeeeeeee eee eeeeeeeeeeeee.[‌88‌] Meeeeee eeeeeeeee eeee eeee eeee eeeeeeee.[‌88‌] Meeeeeeeeeeeee eeeeeee eee eeeeeee eeeeee eee ee eeeeeeee eeee 8 eeeeeeeeeee ee e β-eeeeeeee (ee eee eeee eeeeee eeeeeeee) eee 8 eeeeeeeeee ee eeeeeeeeeeeee.[‌8‌,‌88‌]

‌Meeeee 8‌ Meeeeeeeeee Meeeeeeee ee Meeeeeeeee eee M-Mee-8-eeeeeeeeeeeeeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeee:

8-[Meeeee(eeeeeee)eeeee]-8-(8-eeeeeeeeeeee)eeee-8-ee-8-eee (‌88‌, M8 = 8-MeM8M8; M8 = M8 = M; M8 = Me); Meeeeee Meeeeeeee:[‌8‌]

M eeee ee 8-(8-eeeeeeeeeeee)-8-eeeeeeeeeee (8.88 e, 88 eeee) ee MeMM (8 eM) eee eeeeeee eeee e eeee ee MeMMMM (8.88 e, 88 eeee) ee MeMM (8 eM) ee 88°M. Mee eeeeeee eee eeeeee ee 88°M eee 8 eee eeee eeeeee ee 88°M. Mee eeeeeee eeeeee eeeeee eee eee eeeee 8 eee e eeeeeeeeeee eeeee ee eeee. Meeee 8 e, eee eeeeeee eee eeeeeeee eee eee eeeeeee eee eeeeee eeee MeMM eee eeeee ee eeee eeeeee eeeeeeee; eeeee: 8.88 e (88%).

References

Meeeeee Meeeeeeeeee

• 8.Meeeee-Meee, (8888) M 88-8, 888.