Categories: Synthesis of O-Heterocycles >
Synthesis of 4H-pyrans
Inexpensive and commercially available nano-powder magnetite or iron(III) oxide can be used as catalyst in a new, straightforward, and fast protocol for the construction of 4-substituted-4H-pyrans. The reaction implies a tandem process, involving an aldol condensation, a Michael-type addition, and a dehydrating annulation.
R. Cano, D. J. Ramón, M. Yus, Synlett, 2011, 2017-2019.