Unprecedented Elimination Reactions of Cyclic Aldols: A New Biosynthetic Pathway toward the Taiwaniaquinoid Skeleton Guardia Monteagudo, Juan José Fernández Vargas, Antonio Justicia Ladrón De Guevara, José Zentar, Houda Álvarez-Manzaneda, Ramón Álvarez De Manzaneda Roldán, Enrique Chahboun Karimi, Rachid Bioactive natural products Synthesis Diterpenoids Taiwaniaquinoids Supplementary Materials: The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/molecules28041524/s1, Experimental details of the synthesis of all new substrates. Copy of 1H NMR and 13C NMR spectra of all new compounds. The acid treatment of 6,7-seco-abietane dialdehydes gives, in high yield, the corresponding derivatives with the 4a-methyltetrahydrofluorene skeleton of taiwaniaquinoids. A mechanism involving the elimination of formic acid from the cyclic aldol intermediate is proposed here. This process can be postulated as a new biogenetic pathway from abietane diterpenes to taiwaniaquinoids. Using this novel reaction, the first enantiospecific synthesis of bioactive natural cupresol and taxodal has been obtained. 2023-04-14T07:34:17Z 2023-04-14T07:34:17Z 2023-02-04 journal article Guardia, J.J.; Fernández, A.; Justicia, J.; Zentar, H.; Alvarez-Manzaneda, R.; Alvarez-Manzaneda, E.; Chahboun, R. Unprecedented Elimination Reactions of Cyclic Aldols: A New Biosynthetic Pathway toward the Taiwaniaquinoid Skeleton. Molecules 2023, 28, 1524. [https://doi.org/10.3390/molecules28041524] https://hdl.handle.net/10481/81042 10.3390/molecules28041524 eng http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional MDPI