Total Synthesis of Panaginsene

Abstract The total synthesis of panaginsene has been accomplished in 11 linear steps starting from methyl 3,3‐dimethyl‐5‐oxocyclopent‐1‐ene‐1‐carboxylate. The key steps are a Sharpless asymmetric epoxidation and Ti(III)‐mediated reductive epoxide opening‐radical cyclization to construct the chiral quaternary carbon stereocenter followed by a very challenging HWE olefination reaction on an 1,3‐keto aldehyde and a late stage McMurry olefination using low valent titanium to construct the highly constrained angular tetrasubstituted olefin in a five‐membered ring.