Cyclization of Vinyl Diazo Compounds with Benzofuran-Derived Azadienes Enabled by NaBAr F 4 .

An unprecedented cycloaddition of vinyl diazo compounds with benzofuran-derived azadienes catalyzed by rarely independently used NaBAr F 4 has been established. Benzofuran-fused hydropyridines were constructed with excellent yields and high diastereoselectivity via a Na + -catalyzed inverse-electron-demand aza-Diels-Alder reaction. Notably, this transformation also features good compatibility with a one-pot protocol to deliver the spiro[benzofuran-cyclopentene] skeleton, as well as perfect atom economy and simple reaction conditions.