A new type of imido group donor:: Synthesis and characterization of sulfonylimino-λ3-bromane that acts as a nitrenoid in the aziridination of olefins at room temperature under metal-free conditions
A new type of imido group donor:: Synthesis and characterization of sulfonylimino-λ3-bromane that acts as a nitrenoid in the aziridination of olefins at room temperature under metal-free conditions
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DOI：
10.1021/ja075811i
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发表时间：
2007-10-31
影响因子：
15
通讯作者：
Nakanishi, Waro
中科院分区：
文献类型：
--
作者：
Ochiai, Masahito;Kaneaki, Takao;Nakanishi, Waro
首次合成了一种稳定的磺酰氨基溴CF3SO2N—Br+C6H4-p -CF3，并对其结构进行了表征。x射线晶体学分析表明，“ylidic”Br-N键为中心对称二聚体结构，几乎没有双键特征。在无过渡金属的条件下，亚氨基溴作为一种高效的亚胺基给体，直接对烯烃进行立体氮化反应。所观察到的顺式环烯叠氮化的速率常数与烯烃的浓度成正比。结果表明，烯烃攻击亚氨基溴的sigma(*) N-Br轨道的双分子过渡态参与了类氮转移过程。
A stable sulfonylimino-lambda(3)-bromane, CF3SO2N--Br+C6H4-p -CF3, has been syntesized and structurally characterized for the first time. X-ray crystallographic analyses indicated a centrosymmetric dimer structure with little double-bond character for the "ylidic" Br-N bond. THe iminobromane serves as an efficient imido group donor and directly u ndergoes aziridination of olefins stereospecifically of alkenes under transition-metal-free conditions. The observed rate constants for aziridination of cis -cyclooctene are proportional to concentration of the olefin. The results suggest the involvement of a bimolicular transition state, in which an olefin attacks the sigma(*) N-Br orbital of iminobromane in the nitrenoid transfer process.