Synthetic and Mechanistic Aspects of the Reaction of 1,1-Difluoro-2,2-bis(dimethylamino)ethene with Ethyl Propiolate
作者:Yuelian Xu、Feng Tian、William R. Dolbier
DOI:10.1021/jo990609m
日期:1999.7.1
undergoes a [2 + 2] cycloaddition with ethyl propiolate at -25 degrees C [DeltaH() = 4.2 (+/-0.4) kcal/mol and DeltaS() = -56.7 (+/-0.9) cal/mol.K], and the cyclobutene product undergoes electrocyclic ring opening at +15 degrees C [DeltaH() = 18.5 (+/-0.6) kcal/mol and DeltaS() = -9.7 (+/-1.0) cal/mol.K]. The resultant diene undergoes Diels-Alder reactions with electron-deficient dienophiles to give
1,1-二氟-2,2-双(二甲基氨基)乙烯在-25摄氏度下与丙酸乙酯进行[2 + 2]环加成[DeltaH()= 4.2(+/- 0.4)kcal / mol和DeltaS() = -56.7(+/- 0.9)cal / mol.K],并且环丁烯产物在+15摄氏度下经历环电开环[DeltaH()= 18.5(+/- 0.6)kcal / mol和DeltaS()=- 9.7(+/- 1.0)cal / mol.K]。所得的二烯与缺乏电子的亲二烯物进行狄尔斯-阿尔德反应,得到芳族产物。补充的计算研究解决了[2 + 2]环加成机理的问题。