A versatile catalyst system for enantioselective synthesis of 2-substituted 1,4-benzodioxanes
作者:Eugene Chong、Bo Qu、Yongda Zhang、Zachary P. Cannone、Joyce C. Leung、Sergei Tcyrulnikov、Khoa D. Nguyen、Nizar Haddad、Soumik Biswas、Xiaowen Hou、Katarzyna Kaczanowska、Michał Chwalba、Andrzej Tracz、Stefan Czarnocki、Jinhua J. Song、Marisa C. Kozlowski、Chris H. Senanayake
DOI:10.1039/c8sc05612a
日期:——
We report the synthesis of enantiomerically enriched 1,4-benzodioxanes containing alkyl, aryl, heteroaryl, and/or carbonyl substituents at the 2-position. The starting 1,4-benzodioxines were readily synthesized via ring closing metathesis using an efficient nitro-Grela catalyst at ppm levels. Excellent enantioselectivities of up to 99:1 er were obtained by using the versatile catalyst system [Ir(c
我们报道了2位含有烷基、芳基、杂芳基和/或羰基取代基的对映体富集的1,4-苯并二恶烷的合成。使用有效的硝基-Grela 催化剂,通过闭环复分解很容易合成起始 1,4-苯并二恶英,浓度为 ppm 水平。通过在 2-取代 1,4-苯并二恶英的不对称氢化中使用多功能催化剂体系 [Ir(cod)Cl] 2 /BIDIME-二聚体,获得了高达 99:1 er 的优异对映选择性。此外,DFT 计算表明该过程的选择性是由质子化步骤控制的;基底上的配位基团可能会改变与催化剂的相互作用,从而导致面选择性的变化。