1, l -Dihydroxy-2,2 -binaphthyl

A new approach to the resolution of sulphoxides 242 was recently reported by T oda and coworkers282. It takes advantage of the fact that some sulphoxides form crystalline complexes with optically active 2,2 -dihydroxy-l, 1-binaphthyl 243. When a two-molar excess of racemic sulphoxide 242 was mixed with one enantiomeric form of binaphthyl 243 in benzene-hexane and kept at room temperature for 12 h, a 1 1 complex enriched strongly in one sulphoxide enantiomer was obtained. Its recrystallization from benzene followed by chromatography on silica gel using benzene-ethyl acetate as eluent gave optically pure sulphoxide. However, methyl phenyl sulphoxide was poorly resolved by this procedure and methyl o-tolyl, methyl p-tolyl, s-butyl methyl and i-propyl methyl sulphoxides did not form complexes with 243. 

Dichlorobis( 1 -phenylethoxy)-titanium(IV), 12 Diethyl tartrate, 276 2,2 -Dihydroxy-l, 1 -binaphthyl, 113 Diisopropyl tartrate, 276 Dimethyl tartrate, 124 Ephedrine, 298... 

Toda, F., Tanaka, K., and Nagamatsu, S. (1984) Mutual Optical Resolution of 2,2 -Dihydroxy-l, 1 -binaphthyl and Alkyl Aryl or Dialkyl Sulfoxides by Complex Formation, Tetrahedron Lett., 25, 4929-4932. 

REDUCTION, REAGENTS Bis(triphenyl-phosphine)copper tetrahydroborate. Borane-Pyridine. Calcium-Methylamine/ ethylenediaminc. Chlorobis(cyclopenta-dienyl)tetrahydroboratozirconium(IV). Chromium(II)-Amine complexes. Copper(0)-lsonitrile complexes. 2,2-Dihydroxy-l, 1-binaphthyl-Lithium aluminum hydride. Di-iododimethylsilane. Diisobutyl-aluminum 2,6-di-/-butylphenoxide. Diisobutyl aluminum hydride. Dimethyl sulfide-Trifluoroacetic anhydride. Disodium tetracarbonylferrate. Lithium-Ammonia. Lithium-Ethylenediamine. Lithium bronze. Lithium aluminum hydride. Lithium triethylborohydride. Potassium-Graphite. 1,3-Propanedithiol. Pyridine-Sulfur trioxide complex. 

In 1994 Yamamoto et al. developed a novel catalyst which they termed a "Brmsted acid-assisted chiral Lewis acid" (BLA) [10] (Scheme 1.14, Table 1.3). The catalyst 7 was prepared from (R)-3,3 -dihydroxyphenyl)-2,2 -dihydroxy-l,l -binaphthyl by reaction with B(OMe)3 and removal of methanol [10a, dj. The Brmsted acid is essential for both the high reactivity of the Lewis acid and the high enantioselectivity - the... 

Recrystallization of a 1 1 molecular complex formed from several sulfoxides and (R)-( + )-2,2 -dihydroxy-l, l -binaphthyl (7) allowed resolution of the former22. Conversely, using the optically pure sulfoxide, it was possible to resolve racemic bis-naphthol 7. 

Scheme 4.1 Structure of (R)-6,6-dichloro-2, 2-dihydroxy-l,l-binaphthyl-4,4-bipyridine.

Racemic Crystal-to-Conglomerate Crystal Transformation Reactions in 2,2 -Dihydroxy-1,1 -binaphthyl-l /le4N+CI Complex... 

Binaphthyl molecules (chiral 2,2/-dihydroxy-l,T-binaphthyl) have been studied by Hicks et al., who reported the first experimental observation of CD-SHG on surfaces.4,29,43 In this section, we investigate the nonlinear optical properties of a chiral 1,1-binaphthyl-based helical polymer. 

Potassium triethylborohydride, 260 Sodium borohydride, 21 Ring-forming reactions 2,2 -Dihydroxy-1,1 -binaphthyl, 113 Other asymmetric reactions Camphor-10-sulfonic acid, 62 Di-jjL-chlorobis(l,5-cyclooctadiene)di-rhodium-2,3-0-Isopropylidene-2,3-dihydroxy-1,4-bis(diphenyl-phosphine)butane, 153... 

Dihydroxy-1,1 -binaphthyl and 1,6-Bis(o-chloropheny 1)-1,6-dipheny 1-hexa-2,4-diyne-l,6-diol, Chem. Lett., 509-512.. 

To a solution of 0.015 mmol aluminum catalyst with (/ )-6,6 -dibromo-3,3 -bis (diphenylphosphinoylmethyl)-2,2 -dihydroxy-l,l -binaphthyl as ligand in CH2CI2 was added 0.6 mmol l-methyl-isoquinoUne in 2.25 mL CH2CI2, followed by 160 ixL TMSCN (1.2 mmol) and 91.8 fiL vinyl chloroformate (1.08 mmol) at —60°C. After 48 h, the reaction was quenched by 5% NH3 aqueous solution, and extracted with EtOAc. Upon removal of solvent under reduced pressure, the reside was purified by column chromatography using hexane/EtOAc as the eluent to afford 91% (+)-l-cyano-l-methyl-l,2-dihydroisoquinoline-2-carboxylic acid vinyl ester as a colorless oil, with 84% e.e. as determined by chiral HPLC analysis. 

The chemical compounds, (i )- and (5)-2,2-dihydroxy-1,1-binaphthyl (optical purity, 0.99), are purchased from commercially available sources. The di-substituted binaphthyl derivatives, (i )- and (iS)-l,T-binaphthyl-2,2 -di-[par<2-(zr<2 .s-4- -pentylcyclohexyl)phenoxy-1 -hexyl]ether, are synthesized through the Williamson etherification reactions of chiroptical (i )-(- -)- and (pentyl group (the number of carbon of 5), and hexamethylene chain linked with an ether-type oxygen atom, [-(CH2)60-, 06], and thus abbreviated as PCH506. 

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