An Improved and Practical Method for Synthesizing of α-Sanshools and Spilanthol.

An efficient and practical route for the synthesis of α-sanshools and spilanthol is described herein. Several modifications of an existing method enabled the preparation of the (2,6,8,10)-tetraene precursor of hydroxy-α-sanshool in good yield. A highly selective Wittig reaction employing newly synthesized phosphonium salt with low deliquescence and long-term stability yielded the desired -form tetraene. This improved methodology was shown to be applicable to the efficient synthesis of α-sanshool and spilanthol.