|Structural formulas of the two binol enantiomers|
|Molecular formula||C 20 H 14 O 2|
white to beige powder
|External identifiers / databases|
|Molar mass||286.32 g mol −1|
215-218 ° C
slightly soluble in water
|As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .|
1,1′-Bi-2-naphthol (BINOL) is an organic substance whose ( R ) - or ( S ) -enantiomer is mostly used as a ligand or auxiliary for transition-metal-catalyzed asymmetric synthesis. BINOL has axial chirality ( atropisomerism ). The enantiomers can be separated and are stable to racemization . The specific rotation of the two enantiomers is ± 33-38 ° (20 ° C, 589 nm) (c = 1, THF). BINOL is a precursor to BINAP , another chiral catalyst.
Extraction and presentation
BINOL can be synthesized in high yield (90%) from 2-naphthol in the presence of a copper (II) catalyst with the addition of air or oxygen:
The two enantiomers can be separated, for example, by means of the likewise chiral (8 S , 9 R ) - (-) - N -benzylcinchonidinium chloride. By adding it and dissolving it several times in ethanol, both enantiomers can be isolated in high yield (70–75%).
( R ) - (+) - Binol or ( S ) - (-) - Binol (also derivatives of the pure enantiomers) is mainly used in asymmetric synthesis .
( R ) - (+) - Binol or ( S ) - (-) - Binol is used, for example, as a ligand of a lanthanide in the Shibasaki aldol reaction in order to add unmodified ketones enantioselectively to aldehydes:
Heterobimetal catalysts derived from ( R ) - (+) - binol or ( S ) - (-) - binol are also used in the enantioselective addition of phosphorus nucleophiles to imines .
- ↑ a b data sheet 1,1′-bi-2-naphthol from Sigma-Aldrich , accessed on March 15, 2011 ( PDF ).
- ↑ Data sheet 1,1′-Bi-2-naphthol from Acros, accessed on February 22, 2010.
- ↑ M. Noji, M. Nakajima, K. Koga: "A new catalytic system for aerobic oxidative coupling of 2-naphthol derivatives by the use of CuCl-amine complex: A practical synthesis of binaphthol derivatives", in: Tetrahedron Lett. , 1994 , 35 (43) , pp. 7983-7984; doi: 10.1016 / 0040-4039 (94) 80028-6 .
- ↑ Q.-S. Hu, D. Vitharana, L. Pu: An efficient and practical direct resolution of racemic 1,1′-bi-2-naphthol to both of its pure enantiomers , in: Tetrahedron: Asymmetry , 1995 , 6 (9) , p. 2123-2126; doi: 10.1016 / 0957-4166 (95) 00280-3 .
- ↑ J. Bülle, A. Hittermann: The Basics of Organic Chemistry , Thieme, Stuttgart 2000 ( preview available in the Google Book Search), S. 308th
- ^ H. Gröger , Y. Saida, H. Sasai, K. Yamaguchi, J. Martens and M. Shibasaki : A New and Highly Efficient Asymmetric Route to Cyclic alpha-Amino Phosphonates: The first Catalytic Enantioselective Hydrophosphonylation of Cyclic Imines Catalyzed by Chiral Heterobimetallic Lanthanoid Complexes. In: J. Am. Chem. Soc. 120 ( 1998 ) 3089-3103, doi: 10.1021 / ja973872i .
- ^ I. Schlemminger, Y. Saida, H. Gröger, W. Maison , N. Durot, H. Sasai, M. Shibasaki, J. Martens : Concept of Rigidity: How to Make Enantioselective Hydrophosphonylation of Cyclic Imines Catalyzed by Chiral Heterobimetallic Lanthanoid Complexes almost perfect. In: J. Org. Chem. 65 ( 2000 ) 4818-4825, doi: 10.1021 / jo991882r .