2-amino-2 -hydroxy-3 - 1,1 -binaphthyl

A related approach has recently been reported by Belokon and Kagan et al. These workers used chiral TADDOL-type diols, derived from tartaric acid and 2-amino-2 -hydroxy-1,1 -binaphthyl (NOBIN), as catalysts to obtain yields of up to 95% and enantioselectivity up to 93% ee [59-61], The catalytically active species seem to be the sodium salts of the diols. 

The hydroxy-binaphthyl functionalised saturated imidazolium salt is readily available from 1-amino-I -hydroxy-binaphthyl in a reaction with a ( oc-protected mesitylamine aldehyde [86] (see Figure 4.24). The resulting Schiff base is reduced to the diamine by Na(OAc)3BH. Subsequent deprotection and ring closure reaction with triethyl orthoformate yields the corresponding hydroxy-binaphthyl functionalised saturated imidazolium salt. Reaction with silver(I) carbonate and subsequent carbene transfer to the ruthenium(II) precursor yields the asymmetric olefin metathesis precatalyst. 

Park et al.34,35 have used (S)-2-hydroxy-2 -(3-phenyl-uryl-benzyl)-l,l -binaphthyl-3-carboxaldehyde for conversion of L-amino acids or peptides into D-amino acids [17]. 

Keywords 2-amino-2 -hydroxy-3,-(methoxycarbonyl)-l,l -binaphthyl, SN2 substitution, 2-metliy lamino-2 -hydroxy-3 -carboxy-1,1 -binaphthyl... 

The dendritic 2-amino-2/-hydroxy-l,l/-binaphthyl (NOBIN)-derived Schiff base ligands, displayed in Scheme 6, have been applied in the titanium-... 

RuCl2 P(C6H5)3 3 is used as a precursor in combination with a pyridine-containing derivative of 2-amino-2 -hydroxy-l,T-binaphthyl [272], and an amino bisoxazo-line ligand, AMBOX (16) [273], effecting the enantioselective reduction of several aromatic ketones with up to 98% e.e. The enantioselectivity is decreased by increasing the bulldness of alkyl groups. 

Trost and coworkers developed a chiral zinc phenoxide for the asymmetric aldol reaction of acetophenone or hydroxyacetophenone with aldehydes (equations 62 and 63) . This method does not involve the prior activation of the carbonyls to silyl enol ethers as in the Mukaiyama aldol reactions. Shibasaki and coworkers employed titanium phenoxide derived from a phenoxy sugar for the asymmetric cyanosilylation of ketones (equation 64). 2-Hydroxy-2 -amino-l,l -binaphthyl was employed in the asymmetric carbonyl addition of diethylzinc , and a 2 -mercapto derivative in the asymmetric reduction of ketones and carbonyl allylation using allyltin ° . ... 

To a 125-mL Teflon-lined autoclave was added 5.0 g l,L-bi-2-naphthol (17.5 mmol), 23.5 g (NH4)2S03 H20 (175 mmol), and 65 mL of concentrated aqueous ammonia. The mixture was stirred at 200°C in an oil bath for 5 days. It was then cooled down to ambient temperature and filtered. The resulting solid was washed with water followed by recrystallization from benzene to afford 4.5 g pure 2-amino-2 -hydroxy-l,L-binaphthyl, in a yield of 91%. 

Bile salts are natural and chiral anionic surfactants which form helical micelles of reversed micelle conformation. The first report on enantiomer separation by MEKC using bile salts was the enantioseparation of dansylated DL-amino acids (Dns-o,L-AAs) and, since then, numerous papers have been available. Nonconjugated bile salts, such as sodium cholate (SC) and sodium deoxycholate (SDC), can be used at pH > 5, whereas taurine-conjugated forms, such as sodium taurocholate (STC) and sodium taurodeox-ycholate (STDC), can be used under more acidic conditions (i.e., pH > 3). Several enantiomers, such as diltiazem hydrochloride and related compounds, carboline derivatives, trimetoquinol and related compounds, binaphthyl derivatives, Dhs-dl-AAs, mephenytoin and its metabolites, and 3-hydroxy-l,4-benzodiazepins have been successfully separated by MEKC with bile salts. In general, STDC is considered as the the most effective chiral selector among the bile salts used in MEKC. 

Other ligands such as methoxide are also effective a mechanistic study indicates that the selectivity for cross- rather than homo-coupling is dependent upon the copperdigand ratio.A 1 1 mixture of 2-naphthol and 2-naphthylamine is cross-coupled with CuCl2/benzylamine to give 2-amino-2 -hydroxy-l,l -binaphthyl (68% yield, eq 21). The cross-coupled products from these reactions are important in view of their use as chiral ligands for asymmetric synthesis. 

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