Construction of the Tricyclo[5.3.1.01,5]undecane System by a Tandem Pinacol Rearrangement-Ene Strategy: A Formal Synthesis of (.+-.)-Perhydrohistrionicotoxin.

An advanced synthetic intermediate 4 for perhydrohistrionicotoxin 5 has been synthesized utilizing a novel tandem pinacol rearrangement–ene reaction as a key step.