A general preparation of pyridines and pyridones via the annulation of ketones and esters.
A general preparation of pyridines 4a-f from stabilized ketones 3a-c and aryl ketones 3d-f is described. The annulation of stabilized esters 3g,h gives access to the corresponding 2-pyridones 4g,h. The annulation reactions proceed in fair to excellent yields (46-87%) with vinamidinium hexafluorophosphate salts 2a-d containing electron-withdrawing groups at the beta-position. The mechanism of the reaction was investigated by NMR and proceeds through the formation of a dienaminone intermediate.
Marcoux
J F
JF
Department of Process Research, Merck & Co., Inc., P.O. Box 2000, Rahway, New Jersey 07065, USA. jeff_marcoux@merck.com
Marcotte
F A
FA
Wu
J
J
Dormer
P G
PG
Davies
I W
IW
Hughes
D
D
Reider
P J
PJ