Synthesis of a Diels-Alder Precursor for the Elisabethin A Skeleton

Abstract

A synthesis of a precursor 2 for the Elisabethin A skeleton is reported. Containing a masked quinone and a (E,Z)-diene subunit, it has the required elements for the envisaged intramolecular Diels-Alder reaction to form the tricyclic system of Elisabethin A. Starting from methylresorcinol, the sequence involves the preparation of an arylacetic acid, which was α-alkylated by a chiral building block. Subsequent HWE reaction and cis-selective Wittig olefination furnished the diene with the desired geometry.

total synthesis - natural products - alkylations - Wittig reactions - stereoselectivity

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