A two-step method for the preparation of 3,4-epoxypyrroline derivatives (6-oxa-3-azabicyclo[3.1.0]hex-2-enes) from 2-halo-2H-azirine-2-carboxylates, diazo keto esters, and amines has been developed. 6-Halo-1-oxa-4-azahexa-1,3,5-trienes, prepared in the first step from the azirines and diazo compounds under Rh(II) catalysis, were subjected to nucleophile-induced tandem cyclization to afford highly functionalized rac-(1R,4R,5S)-6-oxa-3-azabicyclo[3.1.0]hex-2-enes in good yields. The stereochemical outcome of the tandem cyclization induced by the secondary amines is rationalized in terms of the structural rigidity of the betaine-type precursor due to the hydrogen bonding between the ammonium group and ester group adjacent to the halogen atom. Post-modification of the 3,4-epoxypyrrolines by the Stille cross-coupling, reduction, and UV-irradiation was also demonstrated.

中文翻译：

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经由亲核加成反应引起的6-卤代-1-氧杂-4-氮杂己三烯的多米诺环化反应的3,4-环氧吡咯啉立体选择性组装

分两步从2-卤代-2- H-叠氮基-2-羧酸酯，重氮酮制备3,4-环氧吡咯啉衍生物（6-oxa-3-azabicyclo [3.1.0] hex-2- enes）的方法已开发出酯和胺。第一步，在Rh（II）催化下，由叠氮基和重氮化合物制备的6-卤代-1-氧杂-4-氮杂六基-1,3,5-三烯经亲核试剂诱导的串联环化反应，以提供高度官能化的化合物rac-（1 R，4 R，5 S）-6-氧杂-3-氮杂双环[3.1.0]己-2-烯具有良好的收率。就甜菜碱型前体的结构刚性而言，仲胺诱导的串联环化的立体化学结果是合理的，这是由于邻近卤素原子的铵基团和酯基团之间存在氢键。还证明了通过Stille交叉偶联，还原和UV辐照对3,4-环氧吡咯啉进行后修饰。