Reactions of Unsaturated Azides; Part 17:An Efficient Strategy for the Synthesis of Small-Ring Heterocycles via Isomerization of 2-Halo-2<i>H</i>-azirines
作者:Klaus Banert、Joseph Rodolph Fotsing
DOI:10.1055/s-2005-918513
日期:——
New acceptor-substituted allenyl halides were synthesized. The addition of hydrazoic acid (HN3) to these allenyl halides led to the formation of new 1-azido-2-haloethene derivatives. The photolysis of the latter compounds afforded the corresponding 2-halo-2H-azirines. At room temperature or below, they isomerized irreversibly by [1,2]-rearrangement of halogen to form other azirine isomers in very good yields. It is the first time that such a complete rearrangement of 2-halo-2H-azirines is observed. This synthetic strategy offers the possibility to observe both azirine isomers in their pure forms from single 1-azido-2-haloethene precursor.
新合成的受体取代丙二烯基卤化物与叠氮酸(HN3)的加成反应,生成了新的1-叠氮-2-卤乙烯衍生物。这些衍生物的光解反应产生了相应的2-卤-2H-氮丙啶。在室温或更低温度下,它们通过卤素的[1,2]-重排不可逆地异构化为其他氮丙啶异构体,产率非常高。这是首次观察到2-卤-2H-氮丙啶如此完整的重排反应。这种合成策略使得从单一的1-叠氮-2-卤乙烯前体中同时获得两种纯形式的氮丙啶异构体成为可能。