Preparation, Crystal Structures, and Spectroscopic and Chemical Properties of 2,4,6-Trifluorophenyl- or 4-(Methoxycarbonyl)phenyl-Substituted (<i>E</i>)-1-(3-Guaiazulenyl)ethylene and (2<i>E</i>,4<i>E</i>)-1-(3-Guaiazulenyl)-1,3-butadiene Derivatives
作者:Shin-ichi Takekuma、Hiroto Matsuoka、Syoutarou Ogawa、Yasutaka Shibasaki、Toshie Minematsu
DOI:10.1246/bcsj.20100069
日期:2010.10.15
Wittig reactions in general provide a mixture of E and Z geometric isomers, while reactions of 2,4,6-trifluorobenzaldehyde [and (E)-3-(2,4,6-trifluorophenyl)propanal] with the Wittig reagent (3-guaiazulenyl)triphenylphosphonium bromide in ethanol containing NaOEt at 25 °C for 24 h under argon give only new E (and 2E,4E)-forms selectively, i.e., (E)-1-(3-guaiazulenyl)-2-(2,4,6-trifluorophenyl)ethylene and (2E,4E)-1-(3-guaiazulenyl)-4-(2,4,6-trifluorophenyl)-1,3-butadiene. For comparative purposes, Wittig reactions of methyl 4-formylbenzoate, 4-(dimethylamino)benzaldehyde, methyl 4-[(E)-2-formylethenyl]benzoate, and (E)-3-[4-(dimethylamino)phenyl]propanal: namely, possessing an electron-withdrawing (–COOCH3) or an electron-donating [–N(CH3)2]} group at the C-4 position of the benzene ring, with (3-guaiazulenyl)triphenylphosphonium bromide in methanol (or ethanol) containing NaOMe (or NaOEt) at 25 °C for 24 h under argon afford a mixture of the corresponding geometric isomers respectively. Along with spectroscopic properties and crystal structures of the isolated products, the chemical behavior of those products toward 1,1,2,2-tetracyanoethylene (TCNE) in benzene at 25 °C for 24 h under argon is reported with a view to comparative study.
维蒂希反应通常提供 E 和 Z 几何异构体的混合物,而 2,4,6-三氟苯甲醛 [和 (E)-3-(2,4,6-三氟苯基)丙醛] 与维蒂希试剂的反应 (3-愈创木薁基)三苯基溴化鏻在含有NaOEt的乙醇中于25℃在氩气下反应24小时仅选择性地产生新的E(和2E,4E)-形式,即(E)-1-(3-愈创木薁基)-2-(2, 4,6-三氟苯基)乙烯和(2E,4E)-1-(3-愈创蓝基)-4-(2,4,6-三氟苯基)-1,3-丁二烯。为了比较,4-甲酰基苯甲酸甲酯、4-(二甲氨基)苯甲醛、4-[(E)-2-甲酰基乙烯基]苯甲酸甲酯和(E)-3-[4-(二甲氨基)苯基]丙醛的维蒂希反应:即在苯环的C-4位上具有吸电子(-COOCH3)或给电子基团[-N(CH3)2]},与(3-愈创蓝基)三苯基溴化鏻在甲醇(或含有NaOMe(或NaOEt)的乙醇)在25℃、氩气下反应24小时,分别得到相应几何异构体的混合物。除了分离产物的光谱性质和晶体结构外,还报告了这些产物在氩气下于 25 °C 下在苯中 24 小时对 1,1,2,2-四氰乙烯 (TCNE) 的化学行为,以进行比较研究。