Microwave-assisted Diels–Alder reactions between Danishefskyʹs diene and derivatives of ethyl α-(hydroxymethyl)acrylate. Synthetic approach toward a biotinylated anti-inflammatory monocyclic cyanoenone

The microwave heating drastically accelerates Diels–Alder cycloadditions between Danishefskyʹs diene and derivatives of ethyl α-(hydroxymethyl)acrylate whose hydroxyl group is protected with various protective groups to give previously unknown adducts, which are necessary as intermediates for the synthesis of a biotin conjugate of a monocyclic cyanoenone with high anti-inflammatory activity. The reaction time is only 1 h and the average yield is approximately 80%. Compared to the traditional thermal conditions this method requires 1/48th to 1/14th of the time and the yields are 2–7 times more.