CuI/BF₃·Et₂O Cocatalyzed Aerobic Dehydrogenative Reactions of Ketones with Benzylamines: Facile Synthesis of Substituted Imidazoles

Abstract

A novel CuI/BF(3)·Et(2)O/O(2)-mediated reaction utilizing ketones and benzylamines for the construction of substituted imidazoles in one step under mild conditions has been demonstrated. This protocol involved the removal of eight hydrogen atoms, the functionalization of four C(sp(3))-H bonds and three new C-N bond formations.

Current advances in the synthesis and biological potencies of tri- and tetra-substituted 1H-imidazoles

“…As a result, a novel, one-step approach was established for the preparation of the highly substituted imidazoles. Remarkably, when BF 3 ·Et 2 O was used as a cocatalyst combined with CuI, a higher reactivity was observed [47].…”

“…Consequently, this method offers a facile, practical, and atom-economic route for the development of polysubstituted imidazoles using gentle conditions. This strategy involves the elimination of eight hydrogen atoms, the functionalization of four C(sp 3 )-H bonds, and the formation of three new C-N bonds in one operation [47].…”

Cu‐Catalyzed Heterocycle Synthesis

“…Eight hydrogen atoms have been removed and four C(sp 3 )-H bonds have been functionalized to form three new C-N bonds in this reaction (Scheme 8.44). This mild and efficient method provides a simple, easy-handling, and atom-economic way for the synthesis of trisubstituted imidazoles [82]. They also realized the Cu(OAC) 2 -catalyzed aminoacetoxylation of Nalkenylamidines using PhI(OAc) 2 as an oxygen source for synthesis of 4-acetoxymethyl-4,5-dihydroimidazoles [84] (Scheme 8.46).…”

I2-catalyzed synthesis of substituted imidazoles from vinyl azides and benzylamines

“…8 Recently, vinyl azides, as attractive and challenging substrates, have drawn much attention for their growing applications in the synthesis of N-heterocyclic compounds. In this reaction, various substituted groups on vinyl azides and benzylamines proceed smoothly and the desired imidazoles are obtained in moderate to good yields.…”

“…8 Recently, vinyl azides, as attractive and challenging substrates, have drawn much attention for their growing applications in the synthesis of N-heterocyclic compounds. 2 The increasing importance of substituted imidazoles has spurred a vigorous research for the development of new synthetic methods.…”