One-pot gold(i)-catalyzed synthesis of 2-pyridonyl alcohols

Abstract

A highly efficient method for the synthesis of 2-pyridonyl alcohols via gold(I) catalyst was developed. The effect of methanesulfonic acid on the reaction progression with the gold catalyst was determined. The proposed mechanism involves intramolecular cyclization product formation derived from 5-exo-dig and 6-exo-dig addition of the nitrogen for 2-propargyloxypyridine and 2-(but-3-yn-1-yloxy)pyridine, respectively. The pyridinium salt formed by the gold(I) catalyst and methanesulfonic acid undergoes a rearrangement reaction in a weakly basic medium (5% aq. Na₂CO₃) to form N-alkenyl pyridonyl alcohols. N-alkenyl pyridonyl alcohols can be obtained in moderate to excellent yields using this method.