Iron‐catalyzed C(5)−H Imidation of Azole with N‐Fluorobenzenesulfonimide

Abstract

An iron(II)-catalyzed direct imidation of oxazole and thiazole with N-fluorobenzenesulfonimide (NFSI) through C(5)ÀH bond cleavage is disclosed, providing C5-imidated azoles in moderate to excellent yields with broad substrate scope. This reaction represents the first iron-catalyzed CÀH imidation of arene where NFSI serves as the imidation reagent, and potentially constitutes an efficient access to C5-functionalized azole with great medicinal significance.

Room‐Temperature C‐H Bromination and Iodination with Sodium Bromide and Sodium Iodide Using N‐Fluorobenzenesulfonimide as an Oxidant

“…Our study commenced with the optimization of reaction conditions for this oxidative halogenation, using N ‐(quinolin‐8‐yl)pivalamide ( 1 a ) as a model substrate, and the results were summarized in Table . Initially, based on our previously reported conditions for the first iron‐catalyzed C−H amination and bisfunctionalization of alkene with NFSI,– quinoline 1 a was indeed be quantitatively brominated with NaBr and NFSI in the presence of catalytic FeCl 2 , affording the C5 ‐brominated product 2 a regioselectively in 98% yield at 70 °C (entry 1). To our delight, it was discovered that neither the iron catalyst nor the high temperature is necessary, and the excellent yield of 2 a could generally be maintained at room temperature (25 °C) in absence of any transition‐metal catalyst (entries 2–3).…”

N-Fluorobenzenesulfonimide: a useful and versatile reagent for the direct fluorination and amination of (hetero)aromatic C–H bonds

“…The only example of utilizing an iron salt as a catalyst in direct amination of aromatic C-H bonds with NFSI was presented by Li et al in 2017. 42 To evaluate the activity of different metal catalysts and ligands, methyl 2-phenylthiazole-4-carboxylate was chosen as the model substrate. Among the various catalysts such as Pd(OAc) 2 , Cu(OAc) 2 , Cu(TFA) 2 , and FeCl 2 ; FeCl 2 was found to be more effective catalyst, which gave a better yield of aminated product.…”

Oxygen Atom Transfer as Key To Reverse Regioselectivity in the Gold(I)-Catalyzed Generation of Aminooxazoles from Ynamides

“…2,5-Diamino-1,3-oxazole (CP-810,123) has been identified as a potential treatment for schizophrenia and Alzheimer’s disease . Despite all these, the synthetic approaches toward these heterocyclic systems are rather limited, and the known methods are based either on the amination , of preprepared oxazoles or on the assembly of the 5-amino-1,3-oxazole − or 2,5-diamino-1,3-oxazole , framework. The main disadvantage of both routes is the usage of complex and/or prefunctionalized substrates.…”