frontier in the development of chiral stationary phases for chromatographic enantioseparation involves homochiral metal–organic frameworks (MOFs). Using enantiopure (R)-2,2′-dihydroxy-1,1′-binaphthalene-6,6′-dicarboxylic acid as a starting material, we prepared three homochiral MOFs that were further used as chiral stationary phases for high-performanceliquidchromatography to separate the enantiomers
Cyclometalated Chiral-at-Ruthenium Catalyst for Enantioselective Ring-Closing C(sp<sup>3</sup>)–H Carbene Insertion to Access Chiral Flavanones
作者:Feng Han、Peter H. Choi、Chen-Xi Ye、Yvonne Grell、Xiulan Xie、Sergei I. Ivlev、Shuming Chen、Eric Meggers
DOI:10.1021/acscatal.2c02423
日期:2022.8.19
A competing oxygen attack pathway involving the formation and [1,2]-shift (Stevensrearrangement) of an oxonium ylide intermediate was successfully suppressed in favor of a catalytic enantioselective ring-closing C(sp3)–H carbene insertion. Density functional theory calculations provide a rationale for the observed C–H insertion over the undesirable C–O formation pathway. The method provides access
Asymmetric Intramolecular Oxa-Michael Addition of Activated α,β-Unsaturated Ketones Catalyzed by a Chiral<i>N</i>,<i>N</i>′-Dioxide Nickel(II) Complex: Highly Enantioselective Synthesis of Flavanones