TMSCl Promoted Direct sp 3 C‐H Alkenylation to Construct ( E )‐2‐Styryl‐tetrahydrobenzo[ d ]thiazoles

A high‐efficient and stereo‐specific approach for the preparation of biologically important ( E )‐2‐styryl‐tetrahydrobenzo[ d ]thiazoles has been developed via TMSCl promoted direct sp 3 C‐H alkenylation of 2‐methyl‐5,6‐dihydrobenzo[ d ]thiazol‐7(4 H )‐one under metal‐free conditions. Seventeen target compounds were synthesized in excellent yields of 82% –98% under the optimal conditions of 300 mol% TMSCl at 110°C for 2 h, and their chemical structures were elucidated by IR, NMR, ESI‐MS, elemental analyses and X‐ray crystallography analysis. A plausible mechanism was also proposed, and this method provided a good functional group conversion for the sp 3 C‐H substrates.