TBAI-assisted direct C-H activation of indoles with β--styrene sulfonyl hydrazides: a stereoselective access to 3-styryl thioindoles.

The current work describes the challenging introduction of a vinyl sulfide group by simple C-H activation on a variety of substrates. The direct C-H activation of indoles with β-()-styrene sulfonyl hydrazides under the sulfenylation conditions, assisted by the iodic catalyst -butyl ammonium iodide (TBAI), afforded a series of ()-styrylthioindoles. Accordingly, β-()-styrene sulfonyl hydrazides undergo radical cross-coupling reactions with a variety of substituted indoles to afford structurally diverse indole vinyl thioethers in moderate to high yields with -stereoselectivity.