Enantioselective one-pot synthesis of 4 H -chromene derivatives catalyzed by a chiral Ni(ii) complex.

A Ni(ii)-bis(oxazoline) complex and p -TSOH are used to form enantioenriched 4 H -chromenes from ortho -quinone methides ( o -QMs) and dicarbonyls, providing the desired products in up to 95% ee. The method is compatible with various β-ketoester substrates, and the products obtained could be converted into biologically active 4 H -chromene derivatives.