Synthetic Approach to Chromone and Flavonoid Piperidine Alkaloids.

Despite the enormous importance of chromone and flavonoid piperidine alkaloids, a general method for their synthesis has not been described. Accordingly, from simple tetrahydro-3-pyridinemethanols () and phenol derivatives (), a synthetic approach to chromone and flavonoid piperidine alkaloids is presented. The access to a novel chromone and flavonoid alkaloid precursors 4-(2-hydroxyphenyl)-3-methylenepiperidines () is achieved in only two steps: Mitsunobu reaction followed by an intramolecular C-H phenolization via an aromatic Claisen rearrangement of the respective Mitsunobu adducts ().