Ruthenium (VIII) Catalysed Dearomative Pyridyl C-X Activation: Direct Synthesis of N- Alkyl-2-pyridones

An efficient synthetic strategy employing pyridyl C-X activation, for the generation of N-alkyl-2-pyridones from N-alkyl-2-halopyridinium salts is described. As pyridones are dearomatised synthetic derivatives of pyridines, a versatile scope exist for pyridyl C-H functionalisation. The present strategy exemplifies a straight forward in-situ generation of Ru(VIII), leading catalytic dearomative synthesis of pyridones. The N-alkyl-2-pyridones are further reduced to N-alkyl-2-piperidones and a plausible mechanism is also drawn, which is supported by some controlled reactions.

Automated summary

This study describes an efficient synthetic strategy using pyridyl C-X activation to generate N-alkyl-2-pyridones from N-alkyl-2-halopyridinium salts. The strategy involves an in-situ generation of Ru(VIII) for catalytic dearomative synthesis of pyridones, which can be further reduced to N-alkyl-2-piperidones. A plausible mechanism is proposed based on controlled reactions.