CH Arylation of Saturated N ‐Heterocycles

Abstract

Saturated N ‐heterocycles having an aryl group are core structures of numerous natural products, pharmaceuticals, chiral catalysts, etc. Therefore, different strategies have been developed for the synthesis of arylated N ‐heterocycles. In contrast to multistep synthesis, the development of direct arylation of saturated N ‐heterocycles has become increasingly popular in recent years. This article summarizes the methods for the synthesis of arylated N ‐heterocycles through direct CH arylation of alicyclic amines.

Iminium and azonium-activated metal and oxidant-free C–H functionalization of aliphatic amines

“…Condensation of carbonyls and amines, and oxidation of amines either via reaction with oxidants or under electrochemical and photochemical conditions are followed as the major pathway for the formation of imine and iminium ions. 2,4 Metal-mediated dehydrogenations and inter- or intramolecular hydride transfer from tertiary amines to a suitable acceptor are also prevalent in the synthesis of imine/iminium ions from amines. 5 Perhaps the preparation of imine/iminium ions via condensation of carbonyl compounds and amines, which was first discovered by Schiff in 1864, 6 is the most common and straightforward method.…”

“…However, a wide variety of reactions for the synthesis of substituted aliphatic N-heterocycles via a more advantageous direct C–H functionalization of aliphatic N-heterocycles have been developed. 2 These reactions often convert relatively less reactive C–H bonds to corresponding reactive intermediates such as α-amino anions, α-amino radicals, α-amino organometallics, iminium ions, etc. , which subsequently react in an intra- or inter-molecular fashion to provide the functionalized alicyclic amines.…”