Total Synthesis of (+)‐Aquaticol by Biomimetic Phenol Dearomatization: Double Diastereofacial Differentiation in the Diels–Alder Dimerization of Orthoquinols with a C2‐Symmetric Transition State

Double or nothing: The bissesquiterpene (+)-aquaticol was synthesized by biomimetic oxidative dearomatization of 1 via an orthoquinol intermediate that undergoes spontaneous and selective dimerization; only like diastereomers react. The remarkable double diastereofacial differentiation observed is explained in terms of a double hyperconjugative “Cieplak–Fallis” effect expressed in a C2-symmetric bispericyclic transition state.