• 10.1021/ol005751k
  • Organic Letters
  • Volume 2
  • May 2000
  • pp 1423-1426

High Turnover Number and Rapid, Room-Temperature Amination of Chloroarenes Using Saturated Carbene Ligands

Reproducible Catalyst System

Details


I need prepare a series of 2-amino-pyridines around 2003, and found this paper by SciFinder. 

I tested the reaction of 1-Boc-piperidine and 2-chloro-3-methyl- pyridine in 50mg scale using 5 mmol% catalysts.

The reactions were not completed in 3h at rt.  When the mixture was shaken at 50 °C for 2h, the reaction was completed.  The separated yield is 80%.

The amine and 2-chloro-3-methyl-spyridines are more hindered than morpholine and 2-chloropyridine exemplified in the paper (Table 1, example 12). 

I scaled up the reaction in 0.6g scale and prepared several  different 2-aminopyridines, all of the reactions went completed in 5h at 50 °C, and the average yields are 65 ~ 90%. 

For each reaction, I tested it in small scale first, then, scaled up.  The catalyst-system is reproducible.

The saturated carbene ligand is easy to handle in small amount (white solid, stable under air, compared to Pd(PPh3)4) . 

In conclusion, I am very happy with this catalyst-system.



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