Access to Polycyclic Thienoindolines via Formal [2+2+1] Cyclization of Alkynyl Indoles with S8 and K2S
Jinhui Ma1, Jiajun Luo2, Kai Jiang2
1Department of Food Science and Engineering, Jinan University, Guangzhou 510632, China.
Abstract:
The syntheses of polycyclic thienoindolines bearing a dihydrothiophene or tetrahydrothiophene subunit have not been reported, despite the fact that such compounds may have interesting medicinal properties. Herein, we report a protocol for accessing polycyclic dihydrothiophenes by means of formal [2+2+1] intramolecular dearomatizing cyclization of alkynyl indoles with K2S and S8 as the sources of sulfide. In addition, tetrahydrothienoindolines were stereoselectively synthesized via a one-pot, two-step protocol involving AgNO3-catalyzed alkenyl dearomatization followed by two nucleophilic addition reactions involving K2S.
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