Highly diastereoselective Diels-Alder cycloadditions of 9R-(1-methoxyethyl)anthracene with p-benzoquinone

Diels - Alder cycloadditions of p-benzoquinone with 9R-(1-methoxyethyl) anthracene provides a 60 : 40 ratio of cycloadducts when heated at reflux in xylene. Mechanistic studies to explore the origins of this selectivity have shown that at lower temperatures the kinetic product predominates, giving a 96 : 4 ratio of cycloadducts.