I2 promoted domino oxidative cyclization for one-pot synthesis of 2-acylbenzothiazoles via metal-free sp3 C–H functionalization

Abstract

An I(2) promoted domino protocol was developed to construct 2-acylbenzothiazoles from simple and readily available aromatic ketones/unsaturated methyl ketones and o-aminobenzenethiols. The reaction proceeded smoothly under metal-free and peroxide-free conditions.

Iodine-mediated synthesis of 3-acylbenzothiadiazine 1,1-dioxides

“…On the basis of this experiment described above and literature [13,35–36], a possible mechanism was proposed in Scheme 7. The halogenation of 1a with iodine results in the formation of compound A , which, via Kornblum oxidation, provides phenylglyoxal B .…”

“…To further probe the reaction process, we monitored the reaction system at 80 °C by 1 H NMR spectroscopic studies. A signal appeared at 9.63 ppm, which was assigned to phenylglyoxal [35] (see Supporting Information File 1). Moreover, intermediate D was isolated after stirring 12 h at 80 °C.…”

Chemoselective Cleavage of C(CO)−C Bond: Molecular Iodine‐Catalyzed Synthesis of Quinazolines through sp3 C−H Bond Functionalization of Aryl Methyl Ketones

“…Over a period of time with the consumption of 1 a and 2 a , there is a significant increase in the concentration of intermediates, thereby producing the desired product 3 a . The peak appearing in between 3.5–4.5 ppm after 6 h is believed to corresponds to the byproduct of HI of inner salt HI– 3 a …”

Metal‐Free Oxidative Carbon‐Heteroatom Bond Formation Through C–H Bond Functionalization

“…In contrast to the above example, an iodine‐promoted domino oxidative cyclization starting from aromatic ketones 200 and 2‐aminobenzenethiols 195 , to give 2‐acylbenzothiazoles 201 , was described recently by Zhu et al (Scheme ) 93. Mechanistically, the method follows a different route from the above example and is similar to the synthesis of oxazoles shown in Scheme .…”