A general one-pot synthesis of pyridines 4a-t from the reaction of dialkyl acyclic/cyclic ketones 1a-i, methyl, aryl/heteroaryl ketones 1m-r, and aldehydes bearing α-hydrogens 1s,t with propargylamine 2 is described. Gold and copper salts are efficient catalysts for the reaction of ketones with 2. The formation of the pyridines 4 is suggested to proceed through the sequential amination of carbonyl compounds followed by regioselective 6-endo-dig cyclization of the N-propargylenamine (N-propargyldienamine) intermediate 3(5) and aromatization reaction. Whereas the preparation of linear polycyclic pyridine 4i can be carried out by reacting cholestan-3-one 1i with 2, the angular polycyclic pyridine 4j has been obtained starting from cholest-5-en-3-one 1j. Selectivity of the reaction of polycyclic dicarbonyls 1k,1 with 2 has also been investigated.
|Titolo:||Sequential Amination/Annulation/Aromatization Reaction of Carbonyl Compounds and Propargylamine : A New One-Pot Approach to Functionalized Pyridines|
|Settore Scientifico Disciplinare:||Settore CHIM/06 - Chimica Organica|
|Data di pubblicazione:||5-set-2003|
|Digital Object Identifier (DOI):||10.1021/jo0347260|
|Appare nelle tipologie:||01 - Articolo su periodico|