Direct Access to <i>N</i>-H-Aziridines from Asymmetric Catalytic Aziridination with Borate Catalysts Derived from Vaulted Binaphthol and Vaulted Biphenanthrol Ligands
作者:Zhenjie Lu、Yu Zhang、William D. Wulff
DOI:10.1021/ja069371r
日期:2007.6.6
The asymmetric catalytic aziridination reaction (AZ reaction) of N-dianisylmethylimines (N-DAM-imines) with ethyl diazoacetate is developed with chiral catalysts prepared from triphenylborate and both the vaulted binaphthol (VANOL) and vaulted biphenanthrol (VAPOL) ligands. Catalysts derived from both ligands were equally effective in terms of asymmetric induction, but the VANOL catalyst was slightly
N-二茴香基甲基亚胺 (N-DAM-亚胺) 与重氮乙酸乙酯的不对称催化氮丙啶化反应 (AZ 反应) 是使用由硼酸三苯酯和拱形联萘 (VANOL) 和拱形联苯蒽 (VAPOL) 配体制备的手性催化剂开发的。衍生自两种配体的催化剂在不对称诱导方面同样有效,但 VANOL 催化剂稍快。使用 VANOL 催化剂可实现高达 400 次转换,同时仍保持氮丙啶产物中 > 或 = 90% ee。配体可以以 95% 的收率回收而不会损失光学纯度。使用芳基亚胺观察到极好的不对称诱导,尽管观察到烷基取代的亚胺的诱导稍低,但来自所有亚胺底物的氮丙啶的光学纯度可以提高到> 或 = 99% ee,单晶。开发了在酸性条件下对 N-DAM-氮丙啶脱保护的方法,而不会引起酸促进的开环。使用烷基取代的氮丙啶和芳基取代的氮丙啶均可获得优异的 NH-氮丙啶收率。最后,用 Boc、甲苯磺酰基和 Fmoc 基团实现了 NH-氮丙啶的