Metal-Free Oxidative Spirocyclization of Alkynes with Sulfonylhydrazides Leading to 3‑Sulfonated Azaspiro[4,5]trienones

A novel and direct oxidative spirocyclization of arylpropiolamides with sulfonylhydrazides leading to 3-sulfonated azaspiro­[4,5]­trienones has been developed under metal-free conditions. The reaction is performed in a tandem manner constituted by the sequential sulfonylation of alkynes, ipso-carbocyclization, dearomatization, hydration, and oxidation processes, providing a convenient and efficient approach to various sulfonated azaspiro­[4,5] trienones of biological importance.本工作报道了一种无金属条件下，芳基丙炔酰胺（arylpropiolamides）与磺酰肼（sulfonylhydrazides）参与的新型直接氧化螺环化反应，可制备3-磺酰化氮杂螺[4,5]三烯酮（3-sulfonated azaspiro[4,5]trienones）。该反应以串联模式进行，依次经历炔烃磺酰化、本位碳环化（ipso-carbocyclization）、脱芳构化（dearomatization）、水合与氧化过程，为各类具备生物活性的磺酰化氮杂螺[4,5]三烯酮提供了便捷高效的合成途径。