Studies on the Synthesis of Elegan-Type Linear Diterpenes: The Efficient Total Syntheses of Eleganolone, Eleganolone Acetate, Elegandiol, Eleganonal, and Epoxyeleganolone

Abstract
The first total syntheses of five elegan-type linear diterpeneseleganolone (1), eleganolone acetate (2), elegandiol (3), eleganonal (4), and epoxyeleganolone (5)were accomplished starting from (E,E)-farnesol (6) via four to six steps, successively, with high overall yield. The key step was the alkylation reaction of silyl cyanide with allylic iodide.