Quinone methides (QMs) are highly reactive intermediates, which may act either as electrophiles 1 or electron poor heterodienes. 2 In fact, QMs have been widely used in organic synthesis, in particular for carrying out 'reverse electron demand' Diels–Alder cycloadditions to give chroman derivatives. 3 It has been suggested that QM-like structures play a key role as intermediates in several biological processes, including enzyme inhibition 4 and DNA cross-linking. 5 ...