11. Tetrabromobenzene can react with butyllithium and furan to form a tetrahydroanthracene 12. The asymmetric hydrogenation of furans and benzofurans has so far proven challenging. 13. Alternatively, rosefuran has been prepared from other furan derivatives. 14. The class of compounds containing such rings are also referred to as furans . 15. Furan is therefore listed as a possible human carcinogen.16. The chemical structure of furanocoumarins consists of a furan ring fused with coumarin. 17. Two unintentionally manufactured families of compounds, dioxins and furans , complete the list. 18. The prototypical structure consists of four six-membered rings and a furan ring. 19. Ma and coworkers developed an alternative method for accessing furans utilizing the Stetter reaction. 20. The resulting epoxycarbonyl can be cyclized to a furan under acidic or basic conditions.
