N,N-Diisopropyl-N-phosphonyl imines lead to efficient asymmetric synthesis of aziridine-2-carboxylic esters
作者:Padmanabha V. Kattamuri、Yiwen Xiong、Yi Pan、Guigen Li
DOI:10.1039/c3ob40251g
日期:——
Highly diastereoselective asymmetric synthesis of chiral aziridine-2-carboxylicesters is reported for 20 examples with good yields (51–87%) and excellent diastereoselectivities (>99 : 1 dr for most cases). The modified N-phosphonyl imines have proven to be superior to previous imine auxiliaries for the aza Darzens reaction by using a secondary isopropyl group to replace the primary benzyl group for
据报道,手性氮丙啶-2-羧酸酯的高度非对映选择性不对称合成有 20 个实例,具有良好的产率(51-87%)和出色的非对映选择性(大多数情况下 >99:1 dr)。通过使用仲异丙基取代N , N的伯苄基,已证明改性N - 膦酰基亚胺在 aza Darzens 反应中优于以前的亚胺助剂。-二氨基保护。同时,发现在 4 Å 分子筛存在的情况下,在该温度下将预冷的亚胺溶液在 -78 °C 下缓慢加入到预先形成的 β-溴化烯醇锂混合物中的特殊操作对产率至关重要和非对映选择性。本方法可以提供对 β-羟基α-氨基酸和其他重要氨基构建块的简单和通用的访问。
Chiral N-phosphonyl imine chemistry: Asymmetric synthesis of α,β-diamino esters by reacting phosphonyl imines with glycine enolates
作者:Teng Ai、Guigen Li
DOI:10.1016/j.bmcl.2009.03.001
日期:2009.7
Chiral phosphonyl imines attached with N-isopropyl protection group were found to react with lithium glycine enolates under convenient conditions to give alpha,beta-diamino esters. Thirteen examples have been examined in good to excellent chemical yields (85-97%) diastereoselectivity (up to 99% de). By treating with HBr at room temperature, the chiral auxiliary can be readily removed and recycled. The absolute structure has been unambiguously determined by converting a product to a known sample. Published by Elsevier Ltd.