Facial Syntheses of Bromobenzothiazines via Catalyst-Free Tandem C–H Amination/Bromination in Water

Abstract

A transition-metal-free and environmentally friendly synthesis method for bromobenzothiazines through tandem C–H amination/bromination was reported. This reaction contains both intramolecular C–H amination and site-selective electrophilic bromination of arenes with NaBr as the bromo source, PhI­(OAc)2 or K2S2O8 as the oxidant, and H2O as the only solvent.

A Catalyst‐Free Minisci‐Type Reaction: the C–H Alkylation of Quinoxalinones with Sodium Alkylsulfinates and Phenyliodine(III) Dicarboxylates

“…and PhI(O 2 CMe) 2 (1.0 equiv.) in CDCl 3 was stirred at room temperature for 1 h. After that, the intermediate PhI(O 2 CMe)O 2 SMe was formed via anion exchange between MeSO 2 Na and PhI(O 2 CMe) 2 (Figure ) …”

“…Based on the above radical trapping and additional experimental results, and previous reports,[7h], [14j], [14k] a possible mechanism of this alkylation reaction is depicted in Scheme . Initially, anion exchange between MeSO 2 Na and PhI(O 2 CR) 2 provides the high reactive intermediate PhI(O 2 CR)O 2 SMe ( A ) . Then, I‐radical B and Me radical ( C ) are generated via decomposition of the intermediate A , releasing SO 2 simultaneously.…”

Manganese(III) Acetylacetonate‐Mediated Phosphorylation of Enamides at Room Temperature

“…We have also tried this reaction using a catalytic amount of Mn(acac) 3 in presence of O 2 or air, but the yield of product is not satisfactory. It should also be pointed out that the C−C coupling products reported by Li's group between acetylacetone, which was the by‐product in our reaction, and enamides were not observed in our reaction conditions.…”

Acid‐Promoted Expeditious Syntheses of Aminated Dibenzosultams via Palladium/Norbornene Cooperatively Catalysed C−H Amination/Arylation

“…Compounds with the privileged scaffold usually demonstrate versatile inhibitory properties [23] . Divergent synthetic methods for assemble of sultams have been established by the group of Zhu, [24b] Wu, [25b] Ma, [25c] Kanai, [26b] and Lei, [26c] including transition‐metal or lewis acid‐catalyzed processes, [24] metal‐free oxidative annulation strategy, [25] and intermolecular cyclization [26] . Inspired by these reports and in continuation of our research interests [11d,e] in Pd/NBE‐catalyzed reaction, we are intrigued whether it would be possible to synthesize benzosultams motif through Catellani‐type reaction using aryl halide with sulfoamide group as linking group, which has not been reported to date.…”