Conjugated Dienyne-Imides as Robust Precursors of 1-Azatrienes for 6π Electrocyclizations to Furo[2,3-b]dihydropyridine Cores

Abstract

A novel strategy to generate functionalized 1-azatriene intermediates for 6π electrocyclizations was developed by using readily accessible dienyne-imides and various terminal olefins under Pd^II catalysis. Taking advantage of the sequential cooperation between preloaded and incorporated functional handles at 1,3-dien-5-yne skeletons, this method not only enables the selective generation of putative 1-azatrienes but significantly accelerates their thermal 6π-electrocyclic ring-closure processes to a series of highly substituted furo[2,3-b]dihydropyridine derivatives in good yields.

Keywords: conjugation; electrocyclic reactions; heterocycles; palladium; synthetic methods.