Synthesis of Thiazoline-Oxazoline Ligands and Their Application in Asymmetric Catalysis
作者:Seán C. McKeon、Helge Müller-Bunz、Patrick J. Guiry
DOI:10.1002/ejoc.201101335
日期:2011.12
series of these ligands was also applied to the chromium-catalyzed Nozaki–Hiyama–Kishi (NHK) allylation of benzaldehyde, affording enantiomeric excess values of up to 85 %. A crystal structure of the most successful ligand in this transformation bound to iron(III) was obtained and demonstrated a tridentate binding mode of the ligand. A transition state is proposed to account for the preferential formation
通过采用收敛路线以高收率合成了一系列包含恶唑啉和噻唑啉单元的新型配体,其中关键步骤是微波辅助钯催化的芳基胺化。新配体在锌催化的吲哚与反式-β-硝基苯乙烯的 Friedel-Crafts 烷基化反应中进行了测试,导致对映体过量值高达 69%。这些配体的完整系列还应用于铬催化的 Nozaki-Hiyama-Kishi (NHK) 苯甲醛烯丙基化,提供高达 85% 的对映体过量值。获得了该转化中最成功的配体与铁 (III) 结合的晶体结构,并证明了配体的三齿结合模式。提出过渡态来解释在 NHK 反应中优先形成 (R) - 对映异构体。