Cu-Catalyzed Three-Component Cascade Synthesis of 1,3-Benzothiazines from ortho-Aminohydrazones and Bromodifluoroacetamides

Abstract

An efficient and convenient synthesis of benzo [d][1,3]thiazine has been developed by employing a copper-catalyzed transformation of readily available ketone-derived hydrazones with elemental sulfur and bromodifluoroalkylative reagents. The strategy involves an S 8 -catalyzed selective triple-cleavage of bromodifluoroacetamides, which acts as a C1 synthon at the 2-position of benzo [d][1,3]thiazine. A mechanism proceeding through a Cu−carbene intermediate is proposed for the C−S bond formation.

Three-Component Assembly of Dihydropyrrolo[3,4-e][1,3]thiazines from Elemental Sulfur, Maleimides, and 1,3,5-Triazinanes

“…The typical Asinger reaction offered a reliable pathway for polysubstituted thiazole synthesis in a multicomponent manner where sulfur powder worked as a sulfur source for preparing sulfur-containing compounds (Scheme , A). Inspired by Asinger’s work, recently, the group of Nguyen, Deng, Song, and others independently demonstrated the crucial role of elemental sulfur in the multicomponent reaction.…”

Base-promoted triple cleavage of CCl2Br: a direct one-pot synthesis of unsymmetrical oxalamide derivatives

“…Extensive research has been conducted on the triple cleavage process (C2 source), but the metal- and photocatalyst-free alternatives have not been as thoroughly explored. 4–6 Moreover, it remains crucial to explore a new reactivity in CCl 2 Br (Fig. 1).…”