A [2 + 3] Reductive Cyclodimerization of Quinoline by SmI2.

@article{Yella2015A,
  title={A [2 + 3] Reductive Cyclodimerization of Quinoline by SmI2.},
  author={Ramesh Yella and Hugo Emilio Gottlieb and Shmaryahu Hoz},
  journal={The Journal of organic chemistry},
  year={2015},
  volume={80 17},
  pages={8929-32}
}
Pyridine and its derivatives are rather difficult to reduce, and the products often undergo a very fast reoxidation to regain aromaticity. The reduction of quinoline by SmI2 results in an instantaneous [2 + 3] cyclization reaction, forming a bridged seven-membered ring within a polycyclic system.