Quinone methides and indole imine methides as intermediates in enantioselective catalysis

As a consequence of their propensity towards aromatization, quinone methides (QMs) and indole imine methides (IIMs) are versatile intermediates in organic synthesis. Although QMs and IIMs have been known for many decades, their application in catalytic asymmetric synthesis, and particularly in organocatalysis, has been achieved only recently. Catalysts for the asymmetric transformations of QMs and IIMs include chiral Brønsted acids, Lewis acids and bases, as well as transition metal complexes. Although the sole activation of either the electrophile or the nucleophile is a viable approach for asymmetric control, dual activation of both reaction partners, particularly by a bifunctional catalyst, has proved to be highly effective in these reactions. In this Review, we discuss advances in this field with a focus on reaction pathways and activation modes, aiming to promote a systematic understanding of the chemistry of QMs and IIMs in asymmetric synthesis.