1, l -Bi-2-naphthol

Three new substituted BINOL ligands, (i )-3-[4,6-bis(dimethylamino)-l,3,5-triazin-2-yl]-l,10-bi-2-naphthol (R)-(72), (i )-3,3 -bis[4,6-bis(dimethylamino)-l,3,5-triazin-2-yl]-l,10-bi-2-naphthol (R)- 73), and 2,4-bis(2,2 -dihydroxy-1,10-binaphthalen-3-yl)-6-(/i-tolyl)-l,3,5-triazine iR,R)-74), have been obtained by directed ort o-lithiation and a Suzuki cross-coupling process (Scheme 10) <2005TA3667>. The titanium complex of (R)-72 was found to be an effective catalyst in the asymmetric addition of diethylzinc to a variety of aromatic aldehydes. 

Prolinamide derivative 40 and (5 )-l,10-bi-2-naphthol was found to be the most effeetive eombination for the addition of aldehydes to nitro-olefins affording the addition products with excellent yields and stereoselection (ee and de up to 99%). 

The seven-membered aromatic cyclic carbonates were obtained from 2,20-biphenol and l,10-bi(2-naphthol), p-nitrophenyl chloroformate, and a tertiary amine as a base. They could be isolated with 80% yield (2, 3, Scheme 13). As was shown by Kricheldorf and Jenssen, disproportionation of 2,20-bis(methoxycarbonyloxy)biphenyl catalyzed by Sn(Oct)2 can also be utilized for obtaining the seven-membered aromatic cyclic carbonate. 

The reaction between epoxides and ammonia is a general and useful method for the preparation of P-hydroxyamines. " Ammonia gives largely the primary amine, but also some secondary and tertiary amines. The useful solvents, the ethanolamines, are prepared by this reaction. For another way of accomplishing this conversion, see 10-54. The reaction can be catalyzed with Yb(OTf)3 and in the presence of a-BINOL is l,l -bi-2-naphthol derivative gives amino alcohols with high asymmetric induction. A variation used Yb(OTf)3 at lOkbar or at ambient pressure. Lithium triflate can also be used. Primary and secondary amines give, respectively, secondary and tertiary amines, for example. 

The ortho coupling of phenoxy radicals is noted in the formation of l,l -bi-2-naphthol from 2-naphthol by oxidation with iron(m) chloride (Expt 6.10). In the case of hindered 2,6-dialkylphenols, a very wide range of oxidants have been found to be variously successful in effecting para coupling further oxidation then occurs to give an extended quinone. 

A useful route toward heteronines is an application of 1,3-dielectrophiles when they react with O- and S-nucleophiles. The chiral (R)-l,l -bi-2-naphthol 152 was reacted with 3-chloro-2-(chloromethyl)prop-l-ene to afford dioxonine 153 (Scheme 28, Section 14.10.6.1) <1998JA5943, 1997TA2921>. A novel procedure for the preparation of cyclic polythioethers by the reaction of dithioiminium salt with 1,3-dihalopropane using phase-transfer catalyst has been reported (Equation 28) <2003PS1295>. This approach avoided the use of thiols, which are not only hard to handle, but also prone to oxidation. 

Hamada et al. have reported the enantioselective, photocatalytic oxidation of (R)-and (S)-l,l -bi-2-naphthol (2 and 3) with [Ru(menbpy)3] 12 a chiral ruthenium complex [93]. A-12 was photoexcited using filtered visible light (X > 400 nm), and the excited complex oxidized by [Co(acac)3], before returning to its ground state oxidation level through reaction with the diol. The (5)-diol was found to be the most reactive of the two enantiomers, and after 13.8% conversion, 2 was present in 15.2% ee (Scheme 10). However, this value was observed to decrease steadily as the percentage conversion increased. 

One of the most popular ligands is BINAP (2,2 -bis(diphenylphosphino)-l,l -binaphthyl)76 which can be made from BINOL (l,l -bi-2-naphthol) through its ditri Hate77 (10.35). (The synthesis of BINOL from 2-naphthol by oxidation with air was given in Chap. 4. Resolution of the BINOL can be accomplished with the inclusion com-... 

Uang found that the activity of vanadium catalysts could be improved by the addition of a Lewis or Bronsted acid. Although almost no reaction was observed with catalyst 22 over 6 h, addition of trimethylsilyl chloride dramatically improved the catalytic activity, affording l,l -bi-2-naphthol in 82% yield with 51% enantiomeric excess after 24 h (Scheme 9.10). Complex 29a, bearing a hydrojy group that can act as a Bronsted acid, also significantly... 

To 0.2 mmol of a solution of (/ )-(+)-l,l -bi(2-naphthol)titanium isopropoxide in toluene in a Schlenk tube were added 0.4 mmol of the aldehyde and 0.45 mmol of allyltributyltin. The solution was stirred at 20 °C over 20 hours, quenched with 1 mL of water, 10 mL of ether was added to the mixture, then the organic layer was washed with water and was dried over MgS04. After evaporation of the solvent, the product was purified by chromatography on silica gel (pentane/ether). 

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