Dual-Ligand-Enabled Ir(III)-Catalyzed Enantioselective C–H Amidation for the Synthesis of Chiral Sulfoxides

A rational
designed Ir­(III)-catalyzed enantioselective C–H
amidation of dibenzyl sulfoxides through desymmetrization and parallel
kinetic resolution is demonstrated. An Ir­(III) complex equipped with
a t-butyl cyclopentadienyl ligand and paired with
a modified chiral proline enables the highly enantioselective sulfoxide-steered
C–H bond activation, providing an efficient and straightforward
way to construct sulfur chiral centers. A wide range of dibenzyl sulfoxides
and dioxazolones are compatible with this process, giving access to
a variety of highly functionalized sulfoxide compounds with synthetically
attractive amide substitution groups in good yields and enantioselectivities.
Moreover, the flexible derivatization of the amidated sulfoxide was
elaborated, providing various types of chiral sulfoxide scaffolds
that would be potentially useful in asymmetric catalysis as chiral
bidentate and tridentate ligands.

本研究展示了一种通过去对称化与并行动力学拆分策略实现的理性设计型三价铱(Ir(III))催化二苄基亚砜对映选择性C-H酰胺化反应。该催化体系采用带有叔丁基环戊二烯基配体的三价铱配合物，并与修饰型手性脯氨酸协同作用，可实现高对映选择性的亚砜导向C-H键活化，为构建硫手性中心提供了高效简洁的合成路径。该反应可兼容多种二苄基亚砜与恶唑酮底物，能够制备一系列带有合成应用价值酰胺取代基的高官能团化亚砜类化合物，且反应收率与对映选择性均表现优异。此外，本研究还对酰胺化亚砜的灵活衍生化进行了系统探究，得到了多种手性亚砜骨架；这类骨架作为手性双齿、三齿配体，在不对称催化领域具备潜在应用价值。