Anodic cyclization reactions and the synthesis of (−)-crobarbatic acid

A synthesis of (−)-crobarbatic acid is reported along with the first use of a vinyl-substituted ketene dithioacetal as a coupling partner for an anodic cyclization reaction. The use of the vinyl-substituted ketene dithioacetal enables the construction of a cyclic product having a tetrasubstituted carbon with a relative stereochemistry opposite to that originally obtained from the cyclization.