Seeking Passe-Partout in the Catalytic Asymmetric Aziridination of Imines: Evolving Toward Substrate Generality for a Single Chemzyme
Seeking Passe-Partout in the Catalytic Asymmetric Aziridination of Imines: Evolving Toward Substrate Generality for a Single Chemzyme
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DOI：
10.1021/jo101160c
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发表时间：
2010-08-20
影响因子：
3.6
通讯作者：
Wulff, William D.
中科院分区：
文献类型：
--
作者：
Mukherjee, Munmun;Gupta, Anil K.;Wulff, William D.
研究了以VANOL和VAPOL为配体制备的硼氧酸盐催化剂对二苯甲基甲基(DAM)胺和四甲基二苯甲胺(MEDAM)亚胺的不对称催化氮杂化反应(AZ反应)。这包括对制备催化剂的不同方案进行评估。考察了由9种不同芳香族和脂肪族醛合成的DAM和Medam亚胺的AZ反应。Medam亚胺在AZ反应中优于DAM亚胺，提供了更高的不对称诱导和更高的氮杂环丙烷总收率。研究发现，Medam亚胺也优于以前研究过的二苯甲基(苯基或Bh)和四叔丁基二苯甲基甲基(BUDAM)亚胺，特别是对于脂肪醛衍生的亚胺。在9种不同的Medam亚胺上，VAPOL催化剂的平均不对称诱导率为97%cc，VANOL催化剂的平均不对称诱导率为96%cc。除一些富含电子的芳醛外，Medam亚胺在所有情况下都可以去保护以得到N-H氮杂环丙烷。Medam亚胺比苯羟基亚胺活性高得多，当重氮乙酸酯被重氮乙酰胺取代时，这一点最为明显。活性较低的重氮乙酰胺在与苯基亚胺的反应中产率很低，但与Medam亚胺的反应产率很高。
The asymmetric catalytic aziridination reaction (AZ reaction) of imines derived from dianisylmethyl (DAM) amine and tetra-methyldianisylmethyl (MEDAM) amine were examined with boroxinate catalysts prepared from both the VANOL and VAPOL ligands. This included an evaluation of different protocols for the preparation of the catalyst. The AZ reaction of DAM and MEDAM imines prepared from nine different aryl and aliphatic aldehydes were examined. The MEDAM imines were superior to the DAM imines in the AZ reaction, giving much higher asymmetric inductions and higher overall yields of aziridines. The MEDAM imines were found to also be superior to the previously studied diphenylmethyl (benzhydryl or Bh) and tetra-tert-butyldianisylmethyl (BUDAM) imines especially for imines derived from aliphatic aldehydes. The average asymmetric induction over the nine different MEDAM imines studied was 97% cc with the VAPOL catalyst and 96% cc with the VANOL catalyst. The MEDAM imines can be deprotected to give N-H aziridines in all cases except for some electron-rich aryl aldehydes. The MEDAM imines are much more reactive than benzhydryl imines, and this was most evident when a diazoacetate ester is replaced by a diazoacetamide. The less reactive diazoacetamides give very low yields in their reactions with benzhydryl imines but high yields with MEDAM imines.