作者:Vera M. Foley、Rafael Cano、Gerard P. McGlacken
DOI:10.1016/j.tetasy.2016.09.001
日期:2016.12
(-)-Sparteine has proven itself to be a highly efficient and versatile ligand. However, in recent years it has become difficult to source. In addition the (+)-enantiomer is also not readily available. Here we report a suite of chiral diamines as potential sparteine surrogates. Chiral trans-1,2-diaminocyclohexane is commercially available in both enantiomeric forms and the parent structure can be easily modified. New (and known) chiral diamines have been tested in the asymmetric silylation of N-Boc pyrrolidine, N-Boc piperidine, the alpha-alkylation of dimethylhydrazones and in the rearrangement of meso-epoxides. While none match the selectivity of the highly evolved natural product, there is certainly potential for this class of diamine ligands to perform in a diverse set of asymmetric transformations. (C) 2016 Elsevier Ltd. All rights reserved.
(-)-Sparteine已被证明是一种高效且多用途的配体。然而,近年来,它变得难以获取。此外,(+)-对映体也不易获得。在此,我们报告了一系列手性二胺作为潜在的 sparteine 代用品。手性反式-1,2-二氨基环己烷的两种对映体形式均可从市场上获得,且其母体结构易于修改。我们测试了新型(和已知)的手性二胺在 N-Boc 吡咯烷、N-Boc 哌啶的不对称硅化,二甲基肼的α-烷基化以及间型环氧化物重排中的表现。虽然没有能够匹配高度进化的天然产物的选择性,但这类二胺配体在一系列不对称转化中表现潜力的确值得肯定。
(E) 2016 Elsevier 有限公司。保留所有权利。