The β-alkylation of pyridine and quinoline 1-oxides with acetylenes: studies of the mechanism

Abstract

Reaction of pyridine and quinoline 1-oxides with phenylcyanoacetylene give products which arise, in part, from the benzoylcyanocarbene but possibly in the main from intermediate (6), ring-opening of which could either lead to 2-alkylated product or to resonancestabilized zwitterion (8); this could close to (7) and thence open to (2); concerted opening of (6) and closure to (7) is also feasible.