Highly Diastereoselective Synthesis of Dihydro-benzoimidazo-[1,3]-thiazines via Electro-oxidative Selenocyclization of Thioallyl Benzoimidazoles

The current methodology reveals a green and proficient electro-oxidative tandem selenocyclization of thioallyl benzoimidazoles manufacturing selenylated dihydro-benzoimidazo-thiazine derivatives. Both C-Se and C-N bond formation were achieved via this mild protocol which exhibits good functional group tolerability affording an extensive range of substrate scope up to 96% isolated yields. Complete control over the regioselective formation of the six-membered heterocycle and stereoselective construction of the contiguous stereocenters was established. The practical electrochemical method operates in an undivided cell at ambient temperature without using any metal and external chemical oxidant.

Automated summary

The methodology involves a green and efficient electro-oxidative tandem selenocyclization of thioallyl benzoimidazoles to produce selenylated dihydro-benzoimidazo-thiazine derivatives. Both C-Se and C-N bond formation are achieved with up to 96% isolated yields. The method exhibits good functional group tolerability and complete control over regioselective formation of the six-membered heterocycle.