Nitroacetylene (1) was prepared by the reaction of NO2PF6 with trimethylsilylacetylene. It is stable at room temperature in dilute solution for about a week. The 1H and 13C NMR spectra of nitroacetylene reveal strong 1H-14N and 13C-14N spin couplings. Nitroacetylene reacts rapidly with nucleophiles. It gives a 1,4-Diels-Alder adduct with cyclopentadiene. However, its reactions with furan and vinyl ethers produce nitrovinylisoxazoles by a mechanism thought to involve the 1,4-addition of nitroacetylene to the vinyl ether to give a highly strained unsaturated nitrone, followed by fragmentation of the nitrone to vinyl nitrile oxide, then additions of this 1,3-dipolarophile.
硝基
乙炔(1)由 NO2PF6 与三甲基
硅基
乙炔反应制备而成。 它在室温稀释溶液中可稳定存在一周左右。硝基
乙炔的 1H 和 13C NMR 光谱显示出很强的 1H-14N 和 13C-14N 自旋耦合。硝基
乙炔与亲核物反应迅速。 它能与
环戊二烯生成 1,4-Diels-Alder 加合物。 不过,它与
呋喃和
乙烯基醚的反应会生成
硝基乙烯基
异噁唑,其机理被认为是硝基
乙炔与
乙烯基醚发生 1,4 加成反应,生成高度紧张的不饱和腈酮,然后腈酮破碎成
乙烯基氧化腈,再加入这种 1,3 双极性化合物。