Cp*Ir(iii)-catalyzed C–H/N–H functionalization of sulfoximines for the synthesis of 1,2-benzothiazines at room temperature

Abstract

The first Cp*Ir(iii)-catalyzed C-H/N-H bond functionalization of sulfoximines with α-diazocarbonyl compounds has been developed for the synthesis of 1,2-benzothiazines under redox-neutral conditions. The reactions proceed at room temperature with excellent functional group tolerance and high yields without the requirement of any silver additive.

Transition‐Metal‐Catalyzed C−H Bond Functionalization of Arenes/Heteroarenes via Tandem C−H Activation and Subsequent Carbene Migratory Insertion Strategy

“…An Ir(III)-catalyzed formation of 1,2-benzothiazines via tandem CÀ H and NÀ H functionalization has been reported by Pawar and co-workers using sulfoximines and acceptoracceptor diazo compounds as the coupling partner (Scheme 41b). [130] The reaction follows a redox-neutral pathway and occurs efficiently at room-temperature. Excellent functional group tolerability with high reaction yields makes the process a robust method to synthesize 1,2-benzothiazine scaffolds.…”

1,2‐Benzothiazine Derivatives from Sulfonimidamides by Metal‐Catalyzed Annulation Reactions in Solution and under Solvent‐Free Mechanochemical Conditions

“…Assuming that elevated temperatures were problematic due to substrate decomposition, an alternative protocol was searched for. In this context, the findings by Pawar, who was able to couple sulfoximines with diazoketones under iridium catalysis at room temperature, caught our attention [9a] . Transferring these conditions with [Cp*IrCl 2 ] 2 (2.5 mol %) as catalyst and PivOH (2.0 equiv.)…”

Rhodium(III)‐Catalyzed C−H Alkynylation of N‐Methylsulfoximines

“…After the pioneering work on rhodium‐catalyzed oxidative annulation of sulfoximines and alkynes from Bolm and co‐workers, several groups have expanded the coupling partners of sulfoximines to diazo compounds, olefins,– pyridotriazoles, 3‐diazoindolin‐2‐imines, α‐MsO/TsO ketones, sulfoxonium ylides, etc . Furthermore, inspired by the well established Rh III catalytic system, several other transition‐metals, including Ru II , Cp*Co III , and Cp*Ir III , have been successfully applied to direct C−H functionalization of sulfoximines. However, to the best of our knowledge, direct alkynylation of C−H bonds of sulfoximines has never been reported and remains as a challenge.…”