A review on the assembly of multi-substituted pyridines via Co-catalyzed [2 + 2 + 2] cycloaddition with nitriles

Org Biomol Chem. 2022 Sep 28;20(37):7391-7404. doi: 10.1039/d2ob01344d.

Abstract

In recent years, many methods for the facile synthesis of pyridines and their derivatives have been developed. The [2 + 2 + 2] cycloaddition reaction of alkynes and nitriles catalyzed by transition metals has emerged as the most straightforward and efficient method to obtain pyridine derivatives. Recently, Earth-abundant cobalt has been employed as a versatile and economical catalyst for the synthesis of functionalized molecules, as compared to other transition metals. This review mainly focuses on the recent research and development of the Co-catalyzed intramolecular [2 + 2 + 2] cycloaddition of diynes-nitriles or intermolecular [2 + 2 + 2] cycloaddition reaction of alkynes or diynes with nitriles for the construction of chiral or achiral multi-substituted pyridines. Meanwhile, brief mechanistic insights are also discussed here to explain the observed regioselectivity.

Publication types

  • Review
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alkynes
  • Catalysis
  • Cobalt
  • Cycloaddition Reaction
  • Diynes
  • Nitriles*
  • Pyridines*

Substances

  • Alkynes
  • Diynes
  • Nitriles
  • Pyridines
  • Cobalt