Biomimetic Synthesis of Santalin A,B and Santarubin A,B, the Major Colorants of Red Sandalwood

Abstract

Better late than never! Almost 200 years after Pelletier's pioneering studies on the chemical constituents of red sandalwood, the major santalins and santarubins have been synthesized. This efficient approach integrates a Knochel isoflavonoid synthesis with Friedel–Crafts allylations or olefin metatheses, and a final biomimetic reaction cascade that furnishes the venerable benzoxanthenone dyes in a single operation (see scheme).