Diastereoselective Total Synthesis of the Euphorbia Diterpenoid Pepluanol A: A Reductive Annulation Approach

A new titanium(III)‐catalyzed reductive annulation constructed a series of diversely functionalized 1,5‐diols in good to excellent yields with respect to a wide scope of vinyl epoxide‐aldehyde substrates. Taken together with a Diels–Alder reaction and a substrate‐controlled diastereoselective cyclopropanation as additional key steps, the synthetic utility of this novel method has been preliminarily explored by the first and concise total synthesis of the Euphorbia diterpenoid (±)‐pepluanol A.