of main observation and conclusion An efficient NaBAr F 4 -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 γand δ-lactams in mostly good to excellent yields with broad substrate scope. Scheme 1 Known knowledge and conceptual advance of this contribution Results and DiscussionWe set out to screen different conditions for this reaction by Chin.