Binaphthyl, 2,2 -dihydroxy resolution

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. 

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. 

Among the preparative methods used for obtaining P-chiral phosphorus compounds, there are procedures involving the use of optically pure auxiliaries like (—)-menthol [40], (—)-ephedrin [41,42], or more recently, the kinetic resolution of 1-hydroxymethylalkylphenylphosphine oxides using Pseudomonas or Candida antarctica lipases [43], It has been found that some [(alkyl-substituted)arene] phosphinates and phosphine oxides can also be resolved efficiently by inclusion complexation with optically active 2,2 -dihydroxy-1, 1 -binaphthyl (17) [44],... 

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. 

Toda, F., and Tanaka, K. (1997) New Chiral Ammonium Salt Hosts Derived from Amino Acids Very Efficient Optical Resolution of 2,2 -Dihydroxy-l,r-binaphthyl by Complexation with These Host Compounds, Chem. Commun., 1087-1088. 

Tanaka, K., Moriyama, A., and Toda, F. (1997) Novel Chiral Recognition in Host-Guest Inclusion Complexes Depending on Their Molar Ratios Efficient Resolution of 2,2 -Dihydroxy-1,1 -binaphthyl Derivatives and CD Spectral Study of Inclusion Complex Crystals, J. Org. Chem., 62, 1192-1193. 

Toda, F., Yoshizawa, K., Hyoda, S., Toyota, S., Chatziefthimiou. S., and Mavridis, I. M. (2004) Efficient Resolution of 2,2 -Dihydroxy-l,l -binaphthyl by Inclusion Complexation with Chiral V-(3-Chloro-2-hydroxypropyi)-A r,Ar,ALtri-... 

Fujimoto, Y. Iwadated, H. Ikekawa, N. Preparation of optically active 2,2 - dihydroxy-1,1 -binaphthyl via microbial resolution of the corresponding racemic diester. J. Chem. Soc., Chem. Commun. 1985, 1333-1334. 

Analytical Properties Resolution of such enantiomeric compounds as 2,2 -dihydroxy-1,1 -binaphthyl and frans-1,2-cyclo hexandiol Reference 29... 

Optically active diols have been used for several asymmetric syntheses [67] and chiral resolutions [68]. In 1990, Kawashima and co-workers [69] reported the first example of direct optical resolution of racemic 2,2 -dihydroxy-l,l -binaphthyl (34) with (R,R)-29. In this procedure equimolar amounts of racemic 34 and (R,R)-29 were added in benzene and the mixture was heated to a homogeneous solution and then cooled to room temperature. After crystallization of the precipitate and treatment with hydrochloric acid, (R)-(+)-34 was obtained with an optical purity of 94% and in a yield of 86% based on the amount of enantiomer presents in the racemate (Scheme 23). 

Scheme 23 Optical resolution of 2,2 -dihydroxy-l,l -binaphthyl (34) with (R,R)-29.

The starting materials (S)-2,2 -dihydroxy-l,l -binaphthyl and (,S)-2,2 -dihydroxy-3,3 -di-methyl-l,l -binaphthyl f(.S )-10 are obtained by resolution or asymmetric synthesis, as discussed in Section 6. 

For the 3,3 -dimethyl derivative 8, several other methods have been developed. The racemic 3,3 -dimethy] compound can be prepared by aminomcthylation of binaphthol with subsequent conversion of the aminomethy] function to a methyl group, and resolved analogously to binaphthol via the phosphoric acid derivative15. Another possibility is the preparation [oxidation of 3-hydroxy-2-naphthoic acid with iron(III) chloride] and resolution [with (S)-leucine methyl ester] of 2,2 -dihydroxy-1,l -binaphthyl-3,3 -dicarboxylic acid (7). 

The well known chiral carbon skeleton designated as binaphthyl hinge has been introduced into asymmetric synthesis and resolution of racemates in the form of the derivatives of 2,2 -dihydroxy-l,r-binaphthyl (84, binaphthol). The application of chiral crown compounds containing this binaphthyl tmit for the separation of amino acids and amino acid esters by use of liquid/liquid chromatography has been described particularly by Cram et al. in detail... 

At first we tried to address the problem with Moreau s method of kinetic resolution which has been applied with great success to compounds of central chirality (ref. 18). To our knowledge this technique has not yet been used for compounds with axial chirality. To be on safe ground, we had to calibrate the effects first with compounds of similar structure and known absolute configuration. We selected 2,2 -dihydroxy-1,1 -binaphthyl (31) as an example and reacted it in the usual way with an excess of racemic 2-phenyl butanoic anhydride in the presence of pyridine. The optical excess in the remaining anhydride was determined by means of the gas chromatographic variant of Brooks and Gilbert (ref. 19) (Scheme 6). 

Before synthetic chiral stationary phases were developed, attempts were made to use naturally occurring chiral materials for the stationary phase. Quartz, wool, lactose and starch were inadequate but triacetylated cellulose has met with some success. The synthetic stationary phases introduced by Pirkle are able to interact with solute enantiomers in three ways, one of which is stereochemically dependent. Typically these interactions are based on hydrogen bonding, charge transfer (rc-donoi -acceptor based) and steric repulsive types. An independent chiral stationary phase therefore consists of chiral molecules each with three sites of interaction bound to a silica (or other) support. Early work in this area demonstrated that 5-arginine bound to Sephadex would resolve 3,4-dihydroxy-phenylalanine, and that direct resolution of chiral helicenes could be accomplished with columns packed with 2-(2,4,5,7-tetranitro-9-fluorenylideneaminoxy)-propionamide or tri-P-naphthol-diphosphate amide. Amino acid esters have also been resolved with a silica bound chiral binaphthyl crown ether, but better separations are achieved with A-acylated amino acid derivatives with amino-acid derived chiral stationary phases. 

The triphenylphosphine-catalyzed reaction of allenyl-diphenylphos-phine oxide with N- and C-nucleophiles gave y-substituted allylphosphine oxides. Scheme 59 shows the outcome of the reaction with phthalimide. " The bisoxide of BINAP was modified by double bromination using NBS in an ionic liquid (hexylmethylimidazolium PFs or Ntfa) (Scheme 60). The resolution of 2,2 -bis(diphenylphosphinoyl)-l,l -binaphthyl was accomplished via an inclusion complex with chiral 2,2 -dihydroxy-l,l -binaphthyl... 

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