ABSTRACT A multicomponent reaction of benzodithiol‐3‐ones, aldehyde, and NH 4 OAc is described herein under mild conditions. A series of 2,3‐dihydro‐4 H ‐benzothiazinones were achieved in one‐pot through a metal‐free cyclization reaction. In the current multicomponent cyclization strategy, organic phosphine serves as the accelerant to accomplish the cleavage of the cyclic S─S bond of benzodithiol‐3‐ones to produce a zwitterionic intermediate in‐situ. This metal‐free ring‐opening of benzodithiol‐3‐ones endowed to afford a vast array of 2,3‐dihydro‐4 H ‐benzothiazinones in good yields with excellent functional group compatibility.
Gu et al. (Sun,) studied this question.