Phosphazene bases and the anionic oxy-Cope rearrangement

Compounds containing a 1,5-hexadien-3-ol system undergo anionic oxy-Cope rearrangement when treated with the phosphazene super-base, P4-t-Bu. The [3,3] sigmatropic rearrangement occurs in hexane as well as in THF. The weaker phosphazene base, P2-Et fails to induce rearrangement. This is the first example of the use of a metal-free base to induce anionic oxy-Cope rearrangement.