Vinyl triflates of α-keto esters react smoothly with primary amines to provide aziridinecarboxylates in good yields. In all cases, little or no stereoselectivity was observed. A mechanistic study has shown that aziridinecarboxylates are strictly formed under kinetic control. The origin of this lack of stereoselectivity is explained by a non- or poorly stereoselective proton transfer.
The effect of ringsubstituents on the cobalt carbonyl-catalyzed carbonylation of functionalized aziridines to β-lactams has been investigated. A variety of aziridines with different substituents and stereochemistry has been synthesized and subjected to carbonylation. The ring expansion to β-lactam takes place in the absence of an electron-withdrawing substituent and higher yields are always obtained
作者:M.Teresa Barros、Christopher D. Maycock、M.Rita Ventura
DOI:10.1016/s0040-4039(02)00791-8
日期:2002.6
α-iodocycloenones in very good yield, by a Michael addition/cyclisation (Gabriel–Cromwell) process employing a slight excess of primaryamine and Cs2CO3 as base at 95°C. Using chiralamines it was possible to prepare optically pure aziridines. The same method was also efficient for the synthesis of aziridines from acyclic α-halounsaturated compounds. 2-Oxoazabicycles reacted with several nucleophiles to afford
通过迈克尔加成/环化(Gabriel-Cromwell)工艺,在95℃下使用略有过量的伯胺和Cs 2 CO 3作为碱,由α-碘代环烯酮以很高的收率制备了氮丙啶。使用手性胺可以制备光学纯的氮丙啶。同样的方法对于由无环α-卤代饱和化合物合成氮丙啶也是有效的。2-氧氮杂双环与几种亲核试剂反应以优异的产率提供了α-杂原子取代的环状烯酮。