Synthesis of 2-thiobenzothiazoles via cascade construction of exocyclic and endocyclic S-C bonds.

The high-value N,S-heterocyclic scaffolds of 2-thiobenzothiazoles (Bth-SR) were efficiently assembled through an atom-economical synthetic strategy employing cascade Cs2CO3-promoted RSH-NCS addition and CuI-catalyzed S-C(sp2) coupling. A library of diverse Bth-SR compounds, including bioactive molecules, was readily afforded in generally high yields from 2-iodoaryl isothiocyanates and thiols under green and benign conditions. Also investigated were the reaction mechanism and the late-stage modifications of Bth-SR.