Abstract Chromenes, isochromenes, and benzoxathioles react with 2, 3-dichloro-5, 6- dicyano-1, 4-benzoquinone to form stable aromatic cations that react with a range of nucleophiles. These oxidative fragment coupling reactions provide rapid access to structurally diverse heterocycles. Conducting the reactions in the presence of a chiral Brønsted acid results in the formation of an asymmetric ion pair that can provide ...