Trost Barry M, Fandrick Daniel R, Dinh Diana C
Department of Chemistry, Stanford University, Stanford, CA 94305-5080, USA.
J Am Chem Soc. 2005 Oct 19;127(41):14186-7. doi: 10.1021/ja0543705.
The dynamic kinetic asymmetric allylic alkylations of racemic allene acetates has been developed with the DACH-phenyl Trost ligand 2 to give general access to allenes with high enantiomeric excess (84-95%) for both malonate and amine nucleophiles. Further, a most unusual dependence of enantioselectivity on base has been uncovered. The magnitude of the enantioselectivity is heavily dependent on the base for the malonate nucleophiles, but the sense and magnitude of the asymmetric induction is dependent on the base for the amine nucleophiles. A Rh(I)-catalyzed intramolecular [4 + 2] cycloaddition of the DYKAT products was accomplished to afford formal Diels-Alder adducts, wherein the axial chirality is faithfully transferred into multiple stereogenic centers as well as olefin geometry.
利用DACH-苯基特罗斯特配体2实现了外消旋丙二烯醋酸酯的动态动力学不对称烯丙基烷基化反应,从而能够以高对映体过量(84-95%)分别为丙二酸酯和胺亲核试剂提供通用的丙二烯合成方法。此外,还发现了对映选择性对碱的一种非常不寻常的依赖性。对映选择性的大小在很大程度上取决于丙二酸酯亲核试剂的碱,但不对称诱导的方向和大小取决于胺亲核试剂的碱。实现了Rh(I)催化的DYKAT产物的分子内[4 + 2]环加成反应,以得到形式上的狄尔斯-阿尔德加合物,其中轴向手性被忠实地转移到多个立体中心以及烯烃几何结构中。