Synthesis of benzosultams via an intramolecular sp²C–H bond amination reaction of o-arylbenzenesulfonamides under metal-free conditions

Abstract

A practical synthetic method for the generation of benzosultams via an intramolecular sp(2) C-H bond amination reaction of o-arylbenzenesulfonamides with PhI(OAc)2-I2 under metal-free conditions is developed. A broad range of substrates are tolerated under mild reaction conditions, affording bioactive benzosultams in good to excellent yields. The resulting benzothiazines could be conveniently transformed into their corresponding iodinated derivatives via electrophilic substitution reactions.

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.…”

Access to [2,1]Benzothiazine S,S-Dioxides from β-Substituted o-Nitrostyrenes and Sulfur

“…1 H NMR (500 MHz, DMSO-d6) δ 8.72 (t, J = 6.0 Hz, 1H), 8.04 (s, 1H), 7.74 (dd, J = 7.9, 1.5 Hz, 1H), 7.53 (td, J = 7.8, 1.5 Hz, 1H), 7.42 -7.32 (m, 4H), 7.27 (td, J = 6.0, 2.7 Hz, 1H), 7.21 (t, J = 7.5 Hz, 1H), 7.14 (d, J = 8.1 Hz, 1H), 4.47 (d, J = 6.0 Hz, 2H). 13 C{1H} NMR (125 MHz, DMSO-d6) δ 159.…”

Recent Advances in Intramolecular Metal‐Free Oxidative C–H Bond Aminations Using Hypervalent Iodine(III) Reagents

“…In 2014, Ding and Wu developed a practical synthetic method for synthesis of 6 H ‐dibenzo[ c , e ][1,2]thiazine 5,5‐dioxides (bioactive benzosultams) 117 with PhI(OAc) 2 –I 2 system via an intramolecular sp 2 C–H bond amination reaction of o ‐arylbenzenesulfonamides 116 in good to excellent yields (Scheme ) . The resulting benzosultams could be easily converted by electrophilic substitution into their corresponding iodinated derivatives 118 .…”