DBU-catalyzed substitution-controlled synthesis of oxa[3.3.1] bridged ring and naphthylamine derivatives

A switchable cascade cyclization reaction of ortho -alkynyl arylketones with amines has been developed. The different reaction pathways are controlled by the substituent on the α-carbon of in situ generated ortho -alkynyl arylaldimines. Under the catalysis of 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), oxa[3.3.1] bridged ring compounds and 1-naphthylamine derivatives are obtained with high yields and excellent regioselectivities. This transformation is metal-free, and has mild reaction conditions, high atom utilization and strong substrate applicability.