Synthetic Utility of 3,5,5-Trialkoxy-1,2,4-trichlorocyclopentadiene. Diels-Alder Adducts in the Preparation of Highly Substituted Aromatic Quinones

Article abstract of DOI:10.1021/jo01298a015

The Diels-Alder reaction of 3,5,5-trialkoxy-1,2,4-trichlorocyclopentadienes with various dienophiles leads to chloro enol ether adducts that can be used synthetically in several ways.When aromatic products are possible, a trifluoroacetic acid (TFA) initiated rearrangement reaction occurs in which quinones having chloro, alkoxy, and carboalkoxy substituents result.If aromatic products are precluded, normal hydrolysis of the chloro enol ether occurs.In TFA these reactions are exclusively initiated by endo protonation of the chloro enol ether moiety.