1,I’-Binaphthyl

A particularly important example is the 2,2 -diol, which is called BINOL. Another important type includes 1, I -binaphthyl diphosphines, such as BINAP. BINOL and BINAP are useful chiral ligands in organometallic compounds that serve as catalysts for hydrogenations and other reactions. In Section 2.5.1.1, we discuss how compounds such as BINOL and BINAP have been used to develop enantioselective hydrogenation catalysts. 

A 2-L, three-necked flask equipped with a Y-tube, magnetic stirrer, dropping funnel topped with a gas bubbler, thermometer, and drying tube is charged with 14.7 g (40.6 mmol) of crude (R)-(-)-methyl 1,I -binaphthyl-2,2 -diyl phosphate and 350 mL of dry toluene. The mixture is stirred under nitrogen and heated with a steam bath until dissolution occurs (44°C). The solution is then cooled in an ice-water bath to 10 C. The cooling bath is removed and a solution of 27.0 mL (91.8 mmol) of Red-Al (Note 6) in 35 mL of toluene is added from the dropping funnel over a 90-m1n period. The mixture... 

B i naphthyl-2-2 -dicarboxylic acid, 1,1 -binaphthyl-2, 2 -dihydrogen phosphate, and 2,2 -dihydroxy-1- I -binaphthyl-S, 3 -dicarboxylic acid 0.04 M Carbonate, pH 9.0, with noncyclooligosaccharides UV 215-235 nm ... 

Diheteroaryl-l,l -binaphthyls were prepared from 2,2 -diiodo-l,T-binaphthyl via microwave assisted cross-coupling by Putala and Kappe using several heteroarylzinc chlorides (2-thienyl)zinc chloride, (2-furyl)zinc chloride, and (3-pyridinyl)zinc chloride (Scheme 3) [22]. Importantly, no racem-ization occurred at the reaction temperature used, giving access to (R)-2,2 -diheter0aryl-1,T-binaphthyls starting from (i )-2,2 -diiodo-l,l -binaphthyl in excellent yields in 1 to 5 min of microwave irradiation. 

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

Bis[2,2 -bis(diphenylphosphine)-l, 1 -binaphthyl](tetrachloro)(triethyl-amine)diruthenium, 36 [2,2 -Bis(diphenylphosphine) -1, T-binaphthyl](dimethanol)rhodium(I) perchlorate, 36... 

RESOLUTION (S)-1 -Amino-2-( silyloxyme-thyOpyrrolidines. I, I -Binaphthyl-2,2 -diyl hydrogen phosphate. t-Butyl hydroperox-ide-Diisopropyl lartrate-Titanium(IV) iso-propoxide. Di-p.-carbonylhexacarbonyldi-cobalt. (2S)-(2a,.3aa,4a,7a,7aa)-2,3,3a,4,5,6,7,7a-Octahydro-7,8,8-trime-thyl-4,7-methanobenzofurane-2-ol. 

The transoid-cisoid equilibrium in crowded binaphthyl compounds generates two enantiomeric cisoid forms which may interconvert. For these compounds, CTI requires heating to proceed (i.e. AG i = 23.5 kcal mol-1 for compound 2, h/2 = 14.5 min at 50 °C). Introduction of substituents increases the barrier to rotation and hence stabilizes the chiral configuration [6]. For example, (S)-1,T-binaphthyl-2,2 -dicarboxylic acid 3 could not be racemized at 175 °C in DMF (Fig. 13.IB). Depending on substituents, racemization may be favored by steric/electro-static repulsions and CTI of dicarboxylate 4 occurs at a lower temperature (AG = 24.4 kcal mol-1 for compound 2, = 51.5 min at 50 °C). 

For asymmetric hydrocarbohydroxylation, an efficient catalyst system consisting of PdCl , CuCH, and (i )-1, r-binaphthyl-2,2 -diyl hydrogen phosphate (BNPPA) was introduced in 1990, and can promote the reaction at ambient tem-... 

Meio-epoxides undergo a ring-opening reaction with aromatic amines in the presence of a chiral metal-organic framework catalyst Zn2(L)(H20)2(A,A -dimethylacetamide)4 where L, [(S)-6,6 -dichloro-2,2 -diethoxy-1,T-binaphthyl-4,4 -bis(5-isophthalic acid)] is an organic linker between the zinc clusters Yields of the a-hydroxyamine ranging i from 70 to 95% with 62-89% ee were obtained using CM-stilbene epoxide and aniline. Lower yields and much lower ee values were found when different substituents were on the stilbene epoxide or the aniline. 

Hydroxy-6-[ 4-sulfo- l-naphthalenyl)azo]-1-naphthalenesulfonic acid, 9CI. T-Hydroxy-1,2 -binaphthyl-4,5 -disulfonic acid. C.I. Acid red 12. C.I. 14835. C.I. Mordant blue 78. Eniacromo blue R. Fast red VR. Omega chrome blue F4B. Carmoisine BL. Azochromol blue F4B [25317-25-3]... 

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. 

The hydroboration of enynes yields either of 1,4-addition and 1,2-addition products, the ratio of which dramatically changes with the phosphine ligand as well as the molar ratio of the ligand to the palladium (Scheme 1-8) [46-51]. ( )-l,3-Dienyl-boronate (24) is selectively obtained in the presence of a chelating bisphosphine such as dppf and dppe. On the other hand, a combination of Pdjldba), with Ph2PC6p5 (1-2 equiv. per palladium) yields allenylboronate (23) as the major product. Thus, a double coordination of two C-C unsaturated bonds of enyne to a coordinate unsaturated catalyst affords 1,4-addition product On the other hand, a monocoordination of an acetylenic triple bond to a rhodium(I)/bisphosphine complex leads to 24. Thus, asymmetric hydroboration of l-buten-3-yne giving (R)-allenyl-boronate with 61% ee is carried out by using a chiral monophosphine (S)-(-)-MeO-MOP (MeO-MOP=2-diphenylphosphino-2 -methoxy-l,l -binaphthyl) [52]. 

The use of chiral C2-symmetric trifluoromethanesulfonamides derived from (i )-1,1 -binaphthyl-2,2 -diamine in similar reactions to those described above has led to the formation of the expected alcohols with enantioselectivities of 43-54% ees. Better enantioselectivities were observed by Paquette et al, resulting from the use of chiral C2-symmetric VERDI (verbenone dimers) disulfonamides derived from the dimerisation of (+ )-verbenone. Stereoselectivity levels ranging from 72 to 98% ee were observed, depending on the structural characteristics of the aldehyde (Scheme 3.45). ... 

In 2000, Woodward et al. reported that LiGaH4, in combination with the S/ 0-chelate, 2-hydroxy-2 -mercapto-1,1 -binaphthyl (MTBH2), formed an active catalyst for the asymmetric reduction of prochiral ketones with catecholborane as the hydride source (Scheme 10.65). The enantioface differentiation was on the basis of the steric requirements of the ketone substituents. Aryl w-alkyl ketones were reduced in enantioselectivities of 90-93% ee, whereas alkyl methyl ketones e.g. i-Pr, Cy, t-Bu) gave lower enantioselectivities of 60-72% ee. 

Recently, catalytic asymmetric Diels-Alder reactions have been investigated. Yamamoto reported a Bronsted-acid-assistcd chiral (BLA) Lewis acid, prepared from (R)-3-(2-hydroxy-3-phcnylphenyl)-2,2 -dihydroxy-1,1 -binaphthyl and 3,5A(trifluoromethy I) - be nzeneboronic acid, that is effective in catalyzing the enantioselective Diels-Alder reaction between a,(3-enals and various dienes.62 The interesting aspect is the role of water, THF, and MS 4A in the preparation of the catalyst (Eq. 12.19). To prevent the trimerization of the boronic acid during the preparation of the catalyst, the chiral triol and the boronic acid were mixed under aqueous conditions and then dried. Using the catalyst prepared in this manner, a 99% ee was obtained in the Diels-Alder reaction... 

Enantioselective hydroxylation of the double bond in C=N nitrones with diphenylsilane, using RU2CI4-I(S)-(—)-p-tolbinap 2(NEh) [p-tolbinap = 2, 2 -bis(di-p-tolylphosphino)-1,1 -binaphthyl] as a catalyst at 0°C, gives the corresponding optically active /V,N -disubstituted hydroxylamines (482). 

---