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
作者:Shin-ichi Takekuma、Kenji Takahashi、Akio Sakaguchi、Masato Sasaki、Toshie Minematsu、Hideko Takekuma
DOI:10.1016/j.tet.2005.11.026
日期:2006.2
Reactions of the title meso forms, (1R,2S)- 1,2-di(2-furyl)- l,2-di(3-gUaiaZUlenyl)ethane (1) and (I R,2S)- 1,2-di(3-guaiazulcnyl)1,2-di(2-thienyl)ethane (2), with a two molar amount of TCNE in benzene at 25 degrees C for 5 h (for 1) and 48 h (for 2) under oxygen give new compounds, 2,2,3,3-tetracyano-4-(2-furyl)-8-isopropyl-6-methyl- 1,4-dihydrocycloheptal.c,d]azulene (3) and 2,2,3,3-tetracyano-8-isopropyl-6-methyl-4-(2-thienyl)- 1,4-dihydrocyclohepta[c,d.]azulene (4), respectively, in 74 and 2 1 % isolated yields. Comparative studies on the above reactions as well as the spectroscopic properties of the unique products 3 and 4, possessing interesting molecular structures, are reported and, further, a plausible reaction pathway for the formation of these products is described. (c) 2005 Elsevier Ltd. All rights reserved.