Synthesis of Substituted 1,2-Dihydropyridines from Propargyl Vinyl Ethers and Allenic Vinyl Ethers by Gold-Catalyzed Claisen Rearrangement and 6π-Aza-electrocyclization

An efficient synthetic method was developed for the construction of substituted 1,2-dihydropyridines by gold-catalyzed tandem reactions. The key intermediates 2,4-dienals were generated from propargyl vinyl ethers or allenic vinyl ethers with gold catalysts. These two reactions involved the process of gold-catalyzed [3,3]-sigmatropic rearrangement/isomerization/amine condensation/6 pi-aza-electrocyclization.