Reactions of (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane with tetracyanoethylene (TCNE) in benzene: comparative studies on the products and their spectroscopic properties

Reactions of the title meso forms, (1R,2S)-1,2-di(2-furyl)-1,2-di(3-guaiazulenyl)ethane () and (1R,2S)-1,2-di(3-guaiazulenyl)-1,2-di(2-thienyl)ethane (), with a two molar amount of TCNE in benzene at 25 °C for 5 h (for ) and 48 h (for ) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl-1,4-dihydrocyclohepta[c,d]azulene () and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)-1,4-dihydrocyclohepta[c,d]azulene (), respectively, in 74 and 21% isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products and , possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described.