Syntheses of p-terphenyls and 11,12-dihydroindeno[2,1-a]fluorene by one-pot benzannulation of Diels–Alder reactions of trans-1,2-dichloroethene and dienes

A series of substituted p-terphenyls and 11,12-dihydroindeno[2,1-a]fluorene were successfully synthesized by one-pot benzannulation of Diels–Alder reaction with 1,2-dichloroethene as an acetylene equivalent dienophile. Two chlorine atoms could be good leaving groups to easily undergo subsequent elimination reactions of Diels–Alder products at a high temperature.