Total Synthesis of (−)-3-Oxoisotaxodione

The first total synthesis of the abietaquinone methide diterpenoid (-)-3-oxoisotaxodione is reported. The key enabling step is the use of a chiral bicyclic hydrazide as an organocatalyst for the enantioselective polyene cyclization of a (Z)-polyene substrate to form the cis-decalin core of the natural product. The α-oxo-para-quinone methide unit is formed by a two-step oxidation from a phenol, enabling an efficient synthesis of the natural product.