gem-Difluorocyclopropenes by [1+2] cycloaddition reactions between difluorocarbene and acetylenes having terminal or internal triple bonds
作者:Yves Bessard、Manfred Schlosser
DOI:10.1016/s0040-4020(01)89734-9
日期:1991.8
method, i.e. by the dissociation of (triphenylphosphonio)difluoromethanide, was found to add to terminal or internal acetylenes with astonishing ease. Actually, it reacts roughly 10 times faster with 4-octyne than with cis-4-octene. The gem-difluorocyclopropenes resulting from the [1+2] cycloaddition process can be isolated with good to excellent yields. They are perfectly stable under anhydrous conditions
发现通过伯顿方法生成的二氟卡宾,即通过(三苯基膦酰基)二氟甲烷的分解,可以很容易地添加到末端或内部的乙炔中。实际上,它与4-辛炔的反应比与顺-4-辛烯的反应快约10倍。可以分离[1 + 2]环加成反应生成的宝石-二氟环丙烯,并获得良好或优异的收率。它们在无水条件下是完全稳定的,而在水性介质中被定量转化为环丙烯酮。-未取代的烯烃环位置迅速经历碱催化的氢/氘交换。估计这种2-烷基-或2-芳基-1,1-二氟环丙烯的酸度高于末端乙炔的酸度。