Chiral Imidazo[1,5-<i>a</i>]pyridine–Oxazolines: A Versatile Family of NHC Ligands for the Highly Enantioselective Hydrosilylation of Ketones
作者:Chinna Ayya Swamy P、Andrii Varenikov、Graham de Ruiter
DOI:10.1021/acs.organomet.9b00526
日期:2020.1.27
report the synthesis and application of a versatile class of N-heterocyclic carbene ligands based on an imidazo[1,5-a]pyridine-3-ylidine backbone that is fused to a chiral oxazoline auxiliary. The key step in the synthesis of these ligands involves the installation of the oxazoline functionality via a microwave-assisted condensation of a cyano-azolium salt with a wide variety of 2-amino alcohols. The
本文中,我们报告了基于咪唑并[1,5- a]的一类多用途的N-杂环卡宾配体的合成和应用融合到手性恶唑啉助剂上的]吡啶-3-吡啶骨架。这些配体合成的关键步骤涉及通过氰基偶氮盐与各种2-氨基醇的微波辅助缩合来安装恶唑啉官能团。所得手性双齿NHC-恶唑啉配体与铑(I)形成稳定的络合物,铑是有效的催化剂,用于结构多样的酮的对映选择性氢化硅烷化。分离出相应的仲醇,收率好(通常> 90%),对映选择性好(极好)(80-93%ee)。报道的氢化硅烷化发生在环境温度(40°C)下,具有出色的官能团耐受性。甚至带有杂环取代基的酮(例如,