Hofmann–Löffler reaction
| Hofmann–Löffler–Freytag reaction | |
|---|---|
| Named after | August Wilhelm von Hofmann Karl Löffler Curt Freytag |
| Reaction type | Ring forming reaction |
In organic chemistry, the Hofmann–Löffler reaction (also referred to as Hofmann–Löffler–Freytag reaction, Löffler–Freytag reaction, Löffler–Hofmann reaction, as well as Löffler's method) is a cyclization reaction with remote C–H functionalization. In the reaction, thermal or photochemical decomposition of N-halogenated amine 1 in the presence of a strong acid (concentrated sulfuric acid or concentrated CF3CO2H) generates a nitrogen radical intermediate. The radical then abstracts an intramolecular hydrogen atom to give a cyclic amine 2 (pyrrolidine or, in some cases, piperidine).