Construction of axially chiral 1-azafluorenes via nickel-catalyzed[2+2+2]cycloaddition of alkynes and(o-alkynyl)benzyl nitriles is described.This strategy enables enantioselective discrimination of two sterically simi...Construction of axially chiral 1-azafluorenes via nickel-catalyzed[2+2+2]cycloaddition of alkynes and(o-alkynyl)benzyl nitriles is described.This strategy enables enantioselective discrimination of two sterically similar ortho substituents,such as H and F,during the construction of tri-ortho-substituted biaryl atropisomers.Mechanistic studies including the stereochemistry model and the stability of the atropenantiomers toward racemization are provided.The unique steric hindrance provided by 1-azafluorene skeleton and the fine chiral cavity of the nickel catalyst are key to achieving high enantioselectivity.展开更多
基金supported by the National Key Research and Development Program of China(2022YFA1502902)the National Natural Science Foundation of China(22371215,22222111,21971198)+2 种基金the Guangdong Basic and Applied Basic Research Foundation(2022A1515012614)the Large-scale Instrument and Equipment Sharing Foundation of Wuhan UniversityChina Postdoctoral Science Foundation(2022M722451)for the financial support。
文摘Construction of axially chiral 1-azafluorenes via nickel-catalyzed[2+2+2]cycloaddition of alkynes and(o-alkynyl)benzyl nitriles is described.This strategy enables enantioselective discrimination of two sterically similar ortho substituents,such as H and F,during the construction of tri-ortho-substituted biaryl atropisomers.Mechanistic studies including the stereochemistry model and the stability of the atropenantiomers toward racemization are provided.The unique steric hindrance provided by 1-azafluorene skeleton and the fine chiral cavity of the nickel catalyst are key to achieving high enantioselectivity.
