20261-65-8Relevant articles and documents
Axially Chiral Bifunctional 8,8′-Biquinolyl: Synthesis of 7,7′-Dihydroxymethyl-8,8′-biquinolyl via Pd-Catalyzed Double C-H Oxidation of 7,7′-Dimethyl-8,8′-biquinolyl
Kitamura, Mitsuru,Fukuma, Hiroaki,Kobayashi, Mitsuaki,Okayama, Shinya,Okauchi, Tatsuo
, p. 3956 - 3960 (2016)
Bifunctional C2-symmetric 7,7′-dihydroxymethyl-8,8′-biquinolyl (2) was synthesized in short steps via (i) Cu/Pd-catalyzed homo coupling of 7-methyl-8-bromoquinoline and (ii) Pd(II)-catalyzed double C-H oxidation. Axial chirality of 2 and its synthetic precursor 7,7′-dimethyl-8,8′-biquinolyl (3) is stable. Optically active 2 was obtained through separation of racemic 2 by chiral column HPLC or Pd(II)-catalyzed double C-H oxidation of optically active 3. The absolute stereochemistry of enantiomers of 2 and 3 was determined using the exciton chirality method.
New 2,2′-substituted 6,6′-dimethylbiphenyl derivatives inducing strong helical twisting power in liquid crystals
Holzwarth, Richard,Bartsch, Richard,Cherkaoui, Zoubair,Solladie, Guy
, p. 3536 - 3541 (2005)
New optically active tetra-ortho-substituted biphenyl chiral dopants for nematic liquid crystals are described. It was shown, with respect to our previous results, that biphenyl chiral dopants bearing only mesogenic residues on their 2,2′-positions and wi
A Versatile Method for Kinetic Resolution of Protecting-Group-Free BINAMs and NOBINs through Chiral Phosphoric Acid Catalyzed Triazane Formation
Jiang, Qianwen,Liu, Wei,Yang, Xiaoyu
, p. 23598 - 23602 (2020/10/23)
A versatile kinetic resolution of protecting-group-free BINAMs and NOBINs has been realized through chiral phosphoric acid catalyzed triazane formation with azodicarboxylates. A series of mono-N-protected and unprotected BINAMs, diphenyl diamines and NOBIN derivatives could be kinetically resolved with excellent performances (with s factor up to 420). The gram-scale reactions and facile derivatizations of the chiral products demonstrate the potential of these methods in the asymmetric synthesis of chiral catalysts and ligands.
Catalytic, Enantioselective Sulfenylation of Ketone-Derived Enoxysilanes
Denmark, Scott E.,Rossi, Sergio,Webster, Matthew P.,Wang, Hao
supporting information, p. 13016 - 13028 (2015/09/15)
A catalytic, enantioselective, Lewis base-catalyzed α-sulfenylation of silyl enol ethers has been developed. To avoid acidic hydrolysis of the silyl enol ether substrates, a sulfenylating agent that did not require additional Br?nsted acid activation, namely N-phenylthiosaccharin, was developed. Three classes of Lewis bases - tertiary amines, sulfides, and selenophosphoramides - were identified as active catalysts for the α-sulfenylation reaction. Among a wide variety of chiral Lewis bases in all three classes, only chiral selenophosphoramides afforded α-phenylthio ketones in generally high yield and with good enantioselectivity. The selectivity of the reaction does not depend on the size of the silyl group but is highly sensitive to the double bond geometry and the bulk of the substituents on the double bond. The most selective substrates are those containing a geminal bulky substituent on the enoxysilane. Computational analysis revealed that the enantioselectivity arises from an intriguing interplay among sterically guided approach, distortion energy, and orbital interactions.
