Nitrone

Nitrones are a group of chemical Verbindungenen in organic chemistry. They contain a functional group, which can be described as an N- oxide of an imine. Nitrones are relatively reactive due to their hybrid charge, such as a 1,3- dipole in addition to electron-rich carbon-carbon bonds.

Representation

Nitrones can be prepared by the reaction of ketones or dienes with two consecutive double bonds with alkylated hydroxylamines. It comes first to a nucleophilic attack of the nitrogen on the carbon of the carbonyl, it creates an intermediate with a positively charged nitrogen and negatively charged oxygen vierbindigem at the former carbonyl. After elimination of water with the former oxygen of the carbonyl and the two hydrogen atoms of the hydroxy-amine is obtained by forming a double bond between nitrogen and carbon nitro structure.

A further possibility is the dehydrogenation of a disubstituted alkyl -substituted hydroxyamine. The N-alkylation of oximes and the oxidative dehydrogenation of secondary amines leads to the nitrones.

Reactions

Nitrones react with alkenes to isoxazolidines. This 1,3-dipolar cycloaddition is strictly cis- selective. Isoxazolidines can be cleaved by catalytic hydrogenation to form β -amino- alcohols.

With terminal alkynes react nitrones in the presence of copper (I ) iodide to the hardly accessible β - lactams. This reaction is also referred to as Kinugasa reaction.