Nitrone

A nitrone is the N-oxide of an imine and a functional group in organic chemistry. The general structure is R1R2C=NR3+O-.

A nitrone is 1,3-dipole in 1,3-dipolar cycloadditions. It reacts with alkenes to an isoxazolidine:


 * [[Image:Nitrone cycloaddition.png|500px|Nitrone cycloadditions]]

One example of this reaction type is the reaction of various Baylis-Hillman adducts with C-Phenyl-N-methylnitrone forming an isoxazolidine in which R1 is phenyl, R2 is hydrogen and R3 is a methyl group.

Nitrones react with terminal alkynes and a copper salt to beta-lactam. This reaction is also called the The Kinugasa reaction for example in this reaction: :



The first step in this reaction is a dipolar cycloaddition of the nitrone with the in situ generated copper(I) acetylide to a 5-membered ring structure which rearranges in the second step.