Divergent Synthesis of Functionalized Indenopyridin-2-ones and 2-Pyridones via Benzyl Group Transfer: Two Cases of Aza-semipinacol-Type Rearrangement

Org Lett. 2022 Nov 25;24(46):8498-8502. doi: 10.1021/acs.orglett.2c03361. Epub 2022 Nov 11.

Abstract

The synthesis of bromo-substituted indeno[1,2-b]pyridin-2-ones and 3-iodo-5-benzyl-substituted 2-pyridones, starting from easily available 6-benzyl-3,6-dihydropyridin-2(1H)-ones, triggered by NBS and NIS, respectively, is described. In both syntheses, a transfer of a benzyl group from the C6 to C5 lactam position occurred, indicating a novel aza-semipinacol-type rearrangement. Identification of intermediate compounds in both transformations supported the proposed reaction mechanisms. In the process of checking the scope of the method's application, functionalized indeno[1,2-b]pyridin-2-ones and 5-benzyl-2-pyridones were obtained.

Publication types

  • Case Reports

MeSH terms

  • Cyclohexenes*
  • Humans
  • Molecular Structure
  • Pyridones*

Substances

  • 2-hydroxypyridine
  • semipinacol
  • Pyridones
  • Cyclohexenes