Semisynthesis of Azedarachol from Pregnanetriol, a Degradative Product of Tigogenin

Abstract We report the first semisynthesis of the natural insect antifeedant azedarachol. The synthesis features the employment of pregnanetriol, a degradative product of the resource natural product tigogenin, as the starting material, the symbiotic reaction involving the mutually‐promoting elimination of toluene‐sulfonate and deprotection of acetonide, and the controllable reactions between the C16‐OH and the C20‐OH in pregnane‐16,20‐diols.