Abstract:
Herein, multiple types of chiral Os(II) complexes have been designed to address the appealing yet challenging asymmetric C(sp3)-H functionalization, among which the Os(II)/Salox species is found to be the most efficient for precise stereocontrol in realizing the asymmetric C(sp3)-H amidation. As exemplified by the enantioenriched pyrrolidinone synthesis, such tailored Os(II)/Salox catalyst efficiently enables an intramolecular site-/enantioselective C(sp3)-H amidation in the γ-position of dioxazolone substrates, in which benzyl, propargyl and allyl groups bearing various substituted forms are well compatible, affording the corresponding chiral γ-lactam products with good er values (up to 99 : 1) and diverse functionality (>35 examples). The unique performance advantage of the developed chiral Os(II)/Salox system in terms of the catalytic energy profile and the chiral induction has been further clarified by integrated experimental and computational studies.
摘要:
在这里,多种类型的手性Os(II)配合物已经被设计来解决吸引人但具有挑战性的不对称C(SP3)-H官能化,其中发现Os(II)/Salox物种对于实现不对称C(sp3)-H酰胺化的精确立体控制最有效。如富含对映体的吡咯烷酮合成所示,这种定制的Os(II)/Salox催化剂可以有效地在二恶唑酮底物的γ位进行分子内位点/对映选择性C(sp3)-H酰胺化,其中苄基,带有各种取代形式的炔丙基和烯丙基是很好的相容,提供具有良好的er值(高达99:1)和不同官能度(>35个实例)的相应手性γ-内酰胺产物。已开发的手性Os(II)/Salox系统在催化能量分布和手性诱导方面的独特性能优势已通过综合实验和计算研究进一步阐明。