A method which avoids metal and halogen for the synthesis of 3-arylthioindoles from indoles and diaryl disulfides using ammonium persulfate in methanol has been presented. Moreover, double C–H sulfenylation of indoles at 2 and 3-positions has also been achieved using iodine and ammonium persulfate.
A transition‐metal‐free dearomative aza‐spirocyclizationreaction of 2,3‐disubstituted indoles is established by using molecular iodine under basic conditions. The required substrates were prepared via sequential Fisher indole synthesis and sulfonylation. This dearomatization reaction is amenable to gram‐scale synthesis, and provides access to various spiroindolenine derivatives from indole sulfonamide
A facile construction of the spiro[indole-3,2′-pyrrolidine] skeleton, through diacetoxyiodobenzene (PIDA) mediated C–N bond-forming dearomatization of C3 sulfonamide linked indole derivatives, has been developed.