A scalable and diversity-oriented synthesis of (±)-paeoveitols

Abstract

Gram scale synthesis of (±)-paeoveitol, a nor-diterpene harboring an unusual benzofuran stitched benzopyran 6/5/6/6 tetracyclic ring system, and its analogues, emanating from bench-top reagents is reported. Scandium triflate-mediated inverse electron demand [4 + 2] cycloaddition reaction between pre-synthesized paeoveitol-D analogue (dienophile) and ortho-quinone methide precursor (diene), both resulting from the same starting material delivered (±)-paeoveitol in decent yield. Fine tuning of the synthetic strategy not only helped to procure scalable quantities of natural product but also provided ample scope to look for the diversity-oriented synthesis of its analogues.