Selective halocyclization and iodosulfonylation of N -benzothiazol-2-yl alkynamides under mild conditions.

The selective halocyclization and iodosulfonylation of N -benzothiazol-2-yl alkynamides under mild conditions is described. An effective synthetic strategy to pyrimidobenzothiazoles via a 6- endo-dig halocyclization of N -benzothiazol-2-yl alkynamides was developed at room temperature with a broad substrate scope. Furthermore, several multisubstituted α,β-enones were synthesized using the same starting materials.