Hoffmann-Loffler reaction

Wolff, M. E. Cyclization of N-halogenated amines (the Hoffmann-Loffler reaction). Chem. Rev. 1963, 63, 55-64. 

Heumann-Pfleger synthesis (indigo) 145 Hinsberg synthesis (thiophene) 98 Hoffmann-Loffler reaction 158 Huisgen synthesis... 

Radical reactions of Hoffmann-Loffler-Freytag type with participation of iodine(III) compounds leading to five-member N-heterocycles 97YGK90. 

Prior to 1958, the only well known examples of functionalization at non activated carbon atoms, in a predictable and specific manner, were those where the Hoffmann-Loffler-Freytag reaction was used. 

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