Palladium-Catalyzed Dynamic Kinetic Asymmetric Transformation of Racemic Biaryls: Axial-to-Central Chirality Transfer
摘要:
The first dynamic kinetic asymmetric transformation of racemic biaryl substrates on the basis of axial-to-central chirality transfer has been realized. Chiral Pd-NHC complexes were found to catalyze the dynamic kinetic asymmetric spiroannulation of 4-(2-bromoaryl)-naphthalen-1-ols (or 2'-bromo-[1,1'-biphenyl]-4-ols) with internal alkynes, affording a series of enantioenriched spirocyclic products bearing an all-carbon quaternary stereocenter in good yields (up to 95%) with excellent enantioselectivities (up to 97% ee).
A novel 4'-(β-alkyloxyethoxy)-4-cyanobiphenyl represented by the general formula:
wherein R represents a straight alkyl group having from 1 to 6 carbon atoms, which is useful as one component of liquid crystal composition having positive dielectric anisotropy.
一种通式如下的新型 4'-(β-烷氧基乙氧基)-4-氰基联苯:
其中 R 代表具有 1 至 6 个碳原子的直烷基,可用作具有正介电常数各向异性的液晶组合物的一种成分。