The enantioselective construction of chiral spirooxindole-based 4-thiazolidinone via asymmetric catalytic formal [3+2] annulation using a bifunctional catalyst
4-Thiazolidinone is regarded as a privileged structural unit in bioactive compounds. However, there is still no example of a catalytic method for the synthesis of chiral 4-thiazolidinone until now. We reported herein a facile and efficient method for the construction of chiral spirooxindole-based 4-thiazolidinone. This methodology is based on the asymmetric formal [3+2] annulation of 1,4-dithiane-2,5-diol to ketimines which is followed by simple oxidation, featuring a broad substrate scope with high enantioselectivity (up to 98% ee). The method has been successfully applied to the synthesis of a novel class of mycobacterium tuberculosis inhibitor-spirooxindole based 4-thiazolidinone.