1,1 -Binaphthalene-2,2 -diol BINOL

Several new azepinium salt catalysts, derived from (- -)- and (—)-5-amino-2,2-dimethyl-4-phenyl-l,3-dioxane 23 [39] and (—)-isopinocamphenylamine 17 moieties, and fused to R or S binaphthalene units [40,41], were directly prepared, in good yields, from the bromomethyl carbaldehyde intermediate 32, which we prepared in turn from commercial R or S (l,l )-binaphthalenyl-2,2 -diol (Binol) (Scheme 5.20, Table 5.4). 

To be accurate, the definition should be restricted to asymmetric reactions catalyzed by a combination of l,r-binaphthalene-2,2 -diol (BINOL, 4) and Ti(0 -Pr)4. Nonetheless, this chapter will give some background on non-chiral Lewis acid promoters, and include other asymmetric catalytic systems. We will not discuss the allylations that are promoted by Lewis bases, which are reviewed elsewhere, nor cover the reactions with other electrophiles. Excellent reviews already exist on "Selective Reactions Using Allylic MetaM and Catalytic Enantioselective Addition of Allylic Organometallic Reagents to Aldehydes and Ketones , as well as in the comprehensive monograph "Modern Carbonyl Chemistry. The use of BINOL-based catalysts in other fields of organic synthesis has also been reviewed. ... 

Mikami and co-workers16-19 have done extensive work for developing catalysts for the asymmetric carbonyl-ene reaction. Excellent enantioselectivites are accessible with the binol-titanium catalyst 17 (Equation (10)) for the condensation of 2-methyl butadiene (R1 = vinyl) and glyoxalates (binol = l,T-binaphthalene-2,2 -diol).16 The products were further manipulated toward the total synthesis of (i )-(-)-ipsdienol. The oxo-titanium species 18 also provides excellent enantioselectivity in the coupling of a-methyl styrene with methyl glyoxalate.17 Reasonable yields and good enantioselectivites are also obtained when the catalyst 19 is formed in situ from titanium isopropoxide and the binol and biphenol derivatives.18... 

Binaphthalene-2,2 -diol-gallium/IM 2-Aryloxy alcohols. meso-Epoxidc Ga—Li linked BINOL complex with high... 

Binaphthalene-2,2 -diol (modifii Aldol reaction. A catalytic a.s i BINOL has been developed. 

The air stable and storable zirconium catalyst, formed from Zr(0 Bu)4, 3,3 -diiodo-l,l -binaphthalene-2,2 -diol (3,3 -l2-BINOL), -propanol and water, with the putative dimeric structure (7.33) also catalyses auft -selective asymmetric aldol reactions. While this process is beheved to proceed through an acyclic transition state, as depicted in Figure 7.2, it is postulated that the greatest steric interaction is now between the silyl enol ether substituent R3 and the bulky Lewis acid resulting in the formation of the fluft -diastereomer predominantly. 

BINOL/titanium catalysts have also been reported (BINOL=l,l -binaphthalene-2,2 -diol) in the allylation of glyoxaldehyde 98. The addition of molecular sieves is extremely important for high reactivity and selectivity. ... 

Nevertheless, A 12 proved to be superior in terms of yield and selectivity. The linker between the two sulfonamide moieties was extensively varied. A pentyl chain showed hereby the best outcome. Making use of the chiral l,l -binaphthyl-2,2 -diol (or l,l -binaphthalene-2,2 -diol or l,l -bi-2-naphthol) (BINOL) backbone, Benaglia designed catalyst A 14, which showed excellent yields (98%) and good enantioselectivities (81%). 

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