Convergent Assembly of 1,4-Benzothiazide Spiroindolinones via [4 + 2] Spiroannulation Under Open-Air Conditions
Wen-Xiang Hu1, Kai-Heng Yu1, Feng-Cheng Jia1
1School of Chemistry and Environmental Engineering, and Key Laboratory of Green Chemical Process, Ministry of Education, Wuhan Institute of Technology, Wuhan 430205, China.
Abstract:
This report discloses a transition-metal-free [4 + 2] spirocyclization of isatin-derived β-silylcarbinols and 2-aminobenzenethiols, providing a facile approach to 1,4-benzothiazide spiroindolinones in decent yields. Control experiments indicate that 3-methylene oxindoles and disulfides are key intermediates in this tandem reaction. Moreover, the resulting products can be facilely converted into pharmaceutically significant sulfone and sulfoxide scaffolds, which further demonstrates the potential utility of this protocol.
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