- An economic, practical access to enantiopure 1,1′-bi-2-naphthols: enantioselective complexation of threo-(1S,2S)-N-benzyl-N,N-dimethyl[1,3-dihydroxy-1-(4′-nitrophenyl)]-2-propylammonium chloride
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An economic, convenient access to enantiopure (R)- and (S)-1,1′-bi-2-naphthol (BINOL) has been discovered. Racemic 1,1′-bi-2-naphthol was reacted with threo-(1S,2S)-N-benzyl-N,N-dimethyl-[1,3-dihydroxyl-1-(4′-nitrophenyl)]-2-propylammonium chloride (BDDNPAC) in water-containing acetonitrile under reflux until the solid dissolved completely, and then cooled to ambient temperature to isolate a yellow-greenish crystal consisting of BDDNPAC, (S)-BINOL, and water, which was analyzed by single crystal X-ray structural analysis. Enantiopure (S)- and (R)-1,1′-bi-2-naphthols were obtained in high yield after decomposition of the colored crystalline complex and evaporation of the acetonitrile solution removed from the complex crystals and successive crystallization. The chiral quaternary ammonium salt BDDNPAC can be recovered and reused without any decrease in efficiency.
- Ha, Wuzu,Shan, Zixing
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- Highly Enantioselective Synthesis and Anticancer Activities of Chiral Conjugated Diynols
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A chiral amino alcohol based ligand was found to promote the highly enantioselective addition of terminal conjugated diynes to aromatic and aliphatic aldehydes. The combination of easily available C2-symmetric (R)- and (S)-BINOL with Ti(OiPr)s
- Zhang, Ke,Zhang, Chun,He, Zhong-Hong,Huang, Jian,Du, Xi,Wang, Li,Wei, Si-Ping,Pu, Lin,Wang, Qin
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p. 2293 - 2299
(2018/10/20)
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- A novel cost-effective thiourea bifunctional organocatalyst for highly enantioselective alcoholysis of meso-cyclic anhydrides: Enhanced enantioselectivity by configuration inversion
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A novel inexpensive thiourea bifunctional organocatalyst which can promote the highly enantioselective (up to 95% ee) alcoholysis of mesocyclic anhydrides has been developed. Computational studies on the catalytic process as well as a synthetic application of this new catalyst are also presented.
- Wang, Su-Xi,Chen, Fen-Er
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supporting information; experimental part
p. 547 - 552
(2009/10/25)
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- Chiral tertiary amine/L-proline cocatalyzed enantioselective Morita-Baylis-Hillman (MBH) reaction
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Four types of chiral amines have been synthesized starting from readily available chiral sources. These chiral amines in combination with L-proline have been found to be efficient cocatalysts for the asymmetric Morita-Baylis-Hillman (MBH) reaction between methyl vinyl ketone (MVK) and aromatic aldehydes. The corresponding adducts were formed in reasonable chemical yields and with good enantioselectivities (up to 83 % ee). Moreover, parallel cocatalytic reactions with the two enantiomers of chiral amine 4 and L-proline revealed that it is the proline stereochemistry that determines the configuration of the newly formed chiral center. In addition, the existence of the free hydroxy group in amine 4a enhanced the enantioselectivity of the reaction. Based on these findings, a plausible mechanism for this cocatalytic MBH reaction has been proposed. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Tang, Hongying,Zhao, Guofeng,Zhou, Zhenghong,Gao, Peng,He, Liangnian,Tang, Chuchi
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p. 126 - 135
(2008/09/18)
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- Highly enantioselective alkynylation of aldehydes catalyzed by a readily available chiral amino alcohol-based ligand
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A new inexpensive chiral amino alcohol-based ligand, (1S,2S)-2-N,N-dimethylamino-1-(p-nitrophenyl)-3-(t-butyl-dimethylsilyloxy) propane-1-ol, was developed for the asymmetric alkynylation of aliphatic and aromatic aldehydes, to prepare the corresponding propargylic alcohols in high yields with up to 99% ee.
- Jiang, Biao,Chen, Zili,Xiong, Wennan
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p. 1524 - 1525
(2007/10/03)
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- Highly enantioselective alkynylation of α-keto ester: An efficient method for constructing a chiral tertiary carbon center
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(matrix presented) The asymmetric addition of terminal alkynes to α-keto ester was carried out using a catalytic amount of (1S,2S)-3-(tert-butyldimethylsilyloxyl)-2-N,N-(dimethylamino)-1-(p-nitrophenyl)- propane-1-ol in the presence of Zn(OTf)2
- Jiang, Biao,Chen, Zili,Tang, Xiaoxia
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p. 3451 - 3453
(2007/10/03)
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- Convenient Synthesis of Chiral 5-Amino-1,3-Dioxanes Built on Some 1-p-Nitrophenylserinols Skeletons
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A simple and rapid methodology for the synthesis of the title compounds is described in order to access polychiral (enantiomerically pure) 5-aminodioxanes in satisfactory yields. The reaction of two nitrophenylserinols with two versatile carbonyl electrophiles (formaldehyde and glyoxal) in very strong acidic conditions (96% H2SO4) is discussed together with the limitations of the method.
- Darabantu, Mircea,Maiereanu, Carmen,Ple, Gerard,Berghian, Camelia,Condamine, Eric,Ramondenc, Yvan
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p. 593 - 598
(2007/10/03)
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