Li, Chaomin Johnson, Richard P. Porco, John A. Total Synthesis of the Quinone Epoxide Dimer (+)-Torreyanic Acid:  Application of a Biomimetic Oxidation/Electrocyclization/Diels−Alder Dimerization Cascade<sup>1</sup> An asymmetric synthesis of the quinone epoxide dimer (+)-torreyanic acid (<b>48</b>) has been accomplished employing [4 + 2] dimerization of diastereomeric 2<i>H</i>-pyran monomers. Synthesis of the related monomeric natural product (+)-ambuic acid (<b>2</b>) has also been achieved which establishes the biosynthetic relationship between these two natural products. A tartrate-mediated nucleophilic epoxidation involving hydroxyl group direction facilitated the asymmetric synthesis of a key chiral quinone monoepoxide intermediate. Thermolysis experiments have also been conducted on a model dimer based on the torreyanic acid core structure and facile retro Diels−Alder reaction processes and equilibration of diastereomeric 2<i>H</i>-pyrans have been observed. Theoretical calculations of Diels−Alder transition states have been performed to evaluate alternative transition states for Diels−Alder dimerization of 2<i>H</i>-pyran quinone epoxide monomers and provide insight into the stereocontrol elements for these reactions. pyran quinone epoxide monomers;stereocontrol elements;Thermolysis experiments;diastereomeric 2 H;chiral quinone monoepoxide;biosynthetic relationship;Theoretical calculations;Diel;model dimer;synthesis;dimerization;hydroxyl group direction;torreyanic acid core structure;Total Synthesis;alternative transition states;pyran monomers;2 H 2003-04-03
    https://acs.figshare.com/articles/dataset/Total_Synthesis_of_the_Quinone_Epoxide_Dimer_-Torreyanic_Acid_Application_of_a_Biomimetic_Oxidation_Electrocyclization_Diels_Alder_Dimerization_Cascade_sup_1_sup_/3642231
10.1021/ja021396c.s002