Asymmetric total syntheses of callistrilones B, G and J

A very concise approach for the first asymmetric and scalable total syntheses of callistrilones B, G and J has been developed. These syntheses proceeded in only 3–4 steps from the commercially available (−)-α-phellandrene (8), without the need for protecting groups. The key feature of the syntheses was a biomimetic, diastereo- and regioselective oxidative [3 + 2] cycloaddition.