Bu₄NI Catalyzed C–N Bond Formation via Cross-Dehydrogenative Coupling of Aryl Ethers (C_sp3–H) and Tetrazoles (N–H)

Abstract

Intermolecular C-N bond formations via cross-dehydrogenative coupling (CDC) of aryl ethers and tetrazoles have been developed under a metal-free condition. In the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and aqueous TBHP, aryl ethers coupled efficiently with tetrazoles to afford hemiaminal ethers. This strategy showed high level of regioselectivity for substrates possessing multiple sp(3) C-H bonds adjacent to the ethereal oxygen.

Cross-dehydrogenative coupling and oxidative-amination reactions of ethers and alcohols with aromatics and heteroaromatics

“…The reactions of ethers, and predominantly of anisole derivatives, were also investigated using the catalytic n -Bu 4 N + I – /peroxide system. 70 Optimization reactions were conducted using anisole and 5-phenyl-2 H -tetrazole at 80–100 °C, with t -BuOOH in decane or in water, aqueous H 2 O 2 , K 2 S 2 O 8 , ( t -BuO) 2 , (PhCOO) 2 , t -BuOOCOPh or PhI(OAc) 2 . t -BuOOH in decane gave a low product yield and the others gave no detectable product.…”

“…Although the products here and those in the immediately preceding section 67 have the same substitution pattern around the tetrazole, in the present work one compound was analyzed using X-ray crystallography to confirm the structure. 70 …”

Synthesis of Quinazolinones, Imidazo[1,2‐c]quinazolines and Imidazo[4,5‐c]quinolines through Tandem Reductive Amination of Aryl Halides and Oxidative Amination of C(sp3)–H Bonds

“…This is consistent with earlier reports in which sodium azide or TMSN 3 was used as an ammonia surrogate to prepare primary amines and nitrogen‐containing heterocycles in a copper‐catalyzed reductive amination reaction of aryl halides . Subsequently, C–N bond formation through a dehydrogenative cross‐coupling (DCC) reaction of a C(sp 3 )–H of DMA and an N–H of the amino group generates intermediate A . This is then oxidized to give cationic intermediate B under oxidative conditions.…”

Recent Progress in the Construction of C−N Bonds via Metal‐Free Radical C(sp3)−H Functionalization

“…In 2015, Patel and co‐workers reported a coupling reaction between tetrazoles and aryl ethers under an ( n‐ Bu) 4 NI/TBHP system. (Scheme ) . Moreover, some hemiaminal ether products from this reaction have been found to exist in various natural products that exhibit a wide range of biological activities.…”