Highly diastereoselective synthesis of benzothiazolo[3,2- a]pyridines via [4 + 2] annulation reaction of 2-vinylbenzothiazoles and azlactones

Org Biomol Chem. 2022 Jun 8;20(22):4512-4517. doi: 10.1039/d2ob00618a.

Abstract

An efficient AgOTf-catalyzed [4 + 2] annulation reaction of 2-vinylbenzothiazoles and azlactones was successfully performed under mild reaction conditions. With this approach, a series of novel benzothiazolo[3,2-a]pyridine derivatives was readily obtained in good to excellent yields (68-96%), with high diastereoselectivities and tolerating quite a broad scope of substituents. By using chiral phosphoric acid catalyst, the desired products were obtained in high enantioselectivities, up to -94%. This methodology provides a rapid and useful method for constructing fused benzothiazole derivatives.

MeSH terms

  • Catalysis
  • Lactones / chemistry*
  • Pyridines*
  • Stereoisomerism
  • Thiadiazoles / chemistry*

Substances

  • Lactones
  • Pyridines
  • Thiadiazoles
  • benzo-1,2,3-thiadiazole