Stereoselective Synthesis of Steroids and Related Compounds, V. Synthesis of (±)‐Chokol A by a Tandem Michael‐Addition/Dieckmann Cyclization

A total synthesis of (±)‐chokol A (rac‐12) was accomplished in five steps by starting from the α,β‐unsaturated ester (E)‐2 in an overall yield of 24%. The key step of this synthesis is the tandem conjugate addition/Dieckmann cyclization of the cuprate derived from vinyl bromide 9 with the α,β‐unsaturated ester (E)‐2.