NaBArF4-Catalyzed Oxidative Cyclization of 1,5-and 1,6-Diynes: Efficient and Divergent Synthesis of Functionalized γ- and δ-Lactams

.Summary of main observation and conclusion An efficient NaBAr4F-catalyzed oxidative cyclization of readily available 1,5- and 1,6-diynes has been developed. Importantly, this transition metal-free oxidative catalysis proceeds via a presumable Lewis acid-catalyzed S(N)2' pathway, which is distinct from the relevant oxidative rhodium and gold catalysis. This method leads to the facile and practical construction of a diverse range of synthetically useful gamma- and delta-lactams in mostly good to excellent yields with broad substrate scope.