1. An excellent overview is available in: Medicinal natural products. A biosynthetic approach, John Wiley & Sons, Chichester (UK), 2002 .
2. For general references, see: , The Diels-Alder reaction. Selected practical methods, John Wiley & Sons, New York (USA), 2002 .
3. See inter alia for 3-vinylbenzofurans:
4. Vinylindenes and Some Heteroanalogs in the Diels-Alder Reaction. X. Dibenzofurans From 3-Vinylbenzofurans
5. 196. Furano-compounds. Part III. Euparin