Recyclization of carbonyl-substituted 4H-chromenes and 1H-benzo[f]chromenes by the action of amidines and guanidine: a novel method for the synthesis of ortho-hydroxybenzylpyrimidines

A series of 2-[(pyrimidin-5-yl)methyl]phenols and 1-[(pyrimidin-5-yl)methyl]-2-naphthols have been accessed via the interaction of carbonyl-substituted 4H-chromenes and 1H-benzo[f]chromenes with amidines and guanidine in a reaction cascade initiated by the Michael reaction. It was established that in this transformation chromenes act as the synthetic equivalents of hydroxybenzylated alpha-formyl ketones or alpha-formylaldehydes.