A Chiral Nanohoop as Highly Efficient Asymmetric Organocatalyst

Опубликована: Авг. 19, 2024

Chiral phosphoric acids are privileged organocatalysts that have been shown to facilitate a large variety of asymmetric transformations. In recent years, the BINOL scaffold has equipped with aromatic groups and transformed into dimeric imidodiphosphates im-prove both chiral induction catalyst turnover by tuning pKa creating confined space around catalytic center. this work, we report an alternative approach for achieving such confinement effect within cavity chiral, shape-persistent “carbon nanohoop” mac-rocycle. We integrated BINOL-derived acid [9]cycloparaphenylene (CPP) employed nanohoop as organocatalyst transfer hydrogenation quinolines. found macrocycle shows excellent activity near-quantitative yields enantioselectivities up 96% ee, which is far supe-rior comparable non-cyclic reference catalysts. While scope quinolines bearing substituents wide, made counterintuitive observation macrocyclic not active smaller alkyl-substituted substrates, indicates highly spe-cific non-covalent effects determine reaction outcome cavity. These results suggest outstanding selectivities can be achieved endowing only supramolecular binding sites but also unusual topologies.

Язык: Английский

A Chiral Nanohoop as Highly Efficient Asymmetric Organocatalyst

Опубликована: Авг. 12, 2024

Chiral phosphoric acids are privileged organocatalysts that have been shown to facilitate a large variety of asymmetric transformations. In recent years, the BINOL scaffold has equipped with aromatic groups and transformed into dimeric imidodiphosphates im-prove both chiral induction catalyst turnover by tuning pKa creating confined space around catalytic center. this work, we report an alternative approach for achieving such confinement effect within cavity chiral, shape-persistent “carbon nanohoop” mac-rocycle. We integrated BINOL-derived acid [9]cycloparaphenylene (CPP) employed nanohoop as organocatalyst transfer hydrogenation quinolines. found macrocycle shows excellent activity near-quantitative yields enantioselectivities up 96% ee, which is far supe-rior comparable non-cyclic reference catalysts. While scope quinolines bearing substituents wide, made counterintuitive observation macrocyclic not active smaller alkyl-substituted substrates, indicates highly spe-cific non-covalent effects determine reaction outcome cavity. These results suggest outstanding selectivities can be achieved endowing only supramolecular binding sites but also unusual topologies.

Язык: Английский

Preparation and evaluation of a 1,1′-bi-2-naphthol-based chiral macrocycle bonded silica chiral stationary phase for high performance liquid chromatography

Journal of Chromatography A, Год журнала: 2024, Номер 1732, С. 465231 - 465231

Опубликована: Авг. 9, 2024

Язык: Английский