Herein we 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 resulting chiral bidentate NHC-oxazoline ligands form stable complexes with rhodium(I) that are efficient catalysts for the enantioselective hydrosilylation of structurally diverse ketones. The corresponding secondary alcohols are isolated in good yields (typically >90%) with good to excellent enantioselectivities (80–93% ee). The reported hydrosilylation occurs at ambient temperatures (40 °C), with excellent functional group tolerability. Even ketones bearing heterocyclic substituents (e.g., pyridine or thiophene) or complex organic architectures are hydrosilylated efficiently, which is discussed further in this report.

中文翻译：

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手性咪唑并[1,5- a ]吡啶-恶唑啉：一种多功能的NHC配体，用于酮的高度对映选择性氢化硅烷化

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，