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,ß-enones were synthesized using the same starting materials.