S — -a- l-NAPHTHYL ETHYLAMINE

Figure 13.14 Some representative chiral stationary phases for gas chromatography. (I), N-lauroyl-S-a-(l-naphthyl) ethylamine (II), N-docosanoyl-L-valine-t-butylamide (III), N-trifluoroacetyl-L-valyl-valine cyclohexyl ester (IV), polymeric chiral phase prepared from polycyanopropylmethylphenylmethyl silicone and L-valine-t-butylamide.

Bertz showed that cuprates such as 460 added to cyclohexenone to give the 3-phenyl derivative (46 1) in optical yields of 0-50%Typical examples are R R N = (45,55)-(+)-5-amino 2,2-dimethyl-4-phenyl-1,3-dioxane (the reaction proceeded in 62% yield, 50% ee) (R) or (S) a-methylbenzylamine (70% yield, 30% ee) (R) or (5) a-(l-naphthyl)ethylamine (70% yield, 30% ee) and (-) a-2-naphthylethyl-amine (50% yield, 40%... 

Fig. 2a, b. Intercalation of a chiral guest molecule, N-trifluoroacetyl-a-phenylethy-lamine, into a H-bonded stack of (R)-N-lauroyl-a-(l-naphthyl)ethylamine a guest of R-configuration, b guest of S-configura-tion [9]... 

Fig. 7-6). Two unichiral amides which have been known capable of this reaction are 1-phenylethylamine [15] and l-(l-naphthyl)ethylamine [16]. Marfey s reagent [N-a-(2,4-dinitro-5-fluorophenyl)-L-alaninamide] was introduced as a reagent to deriva-tize amino acids with cyclopentane, tetrahydroisoquinoline or tetraline structures [17]. Simple chiral alcohols such as 2-octanol can also be used to derivatize acids such as 2-chloro-3-phenylmethoxypropionic acid [18]. 

The spiro compound 206 was prepared in five steps from (S)-l-naphthyl-ethylamine and was composed of a mixture of imine and enamine tautomers. Reduction of the imine function by sodium borohydride occurred on the less hindered si face, leading to the diamine with the R configuration of the newly formed stereo center, then the N-benzyl substituent was removed by hydrogenolysis to give 207 with good overall yield [98] (Scheme 30). 

An attractive alternative to these novel aminoalcohol type modifiers is the use of 1-(1-naphthyl)ethylamine (NEA, Fig. 5) and derivatives thereof as chiral modifiers [45-47]. Trace quantities of (R)- or (S)-l-(l-naphthyl)ethylamine induce up to 82% ee in the hydrogenation of ethyl pyruvate over Pt/alumina. Note that naphthylethylamine is only a precursor of the actual modifier, which is formed in situ by reductive alkylation of NEA with the reactant ethyl pyruvate. This transformation (Fig. 5), which proceeds via imine formation and subsequent reduction of the C=N bond, is highly diastereoselective (d.e. >95%). Reductive alkylation of NEA with different aldehydes or ketones provides easy access to a variety of related modifiers [47]. The enantioselection occurring with the modifiers derived from NEA could be rationalized with the same strategy of molecular modelling as demonstrated for the Pt-cinchona system. 

Although these enantioselective photoreactions are limited to amide or salt derived from achiral acid and chiral amine, one enantioselective photoisomerization reaction of cobaloxime coordinated with chiral axial ligands such as 1-methylpropylamine, l-(l-naphthyl)ethylamine, and 2-phenylglycinol has been reported. For example, finely powdered (2-cyanoethyl)cobaloxime (60), suspended in liquid paraffin and spread onto a Petri dish, was irradiated to give (S)-(-)-61 of about 80% ee after displacement of the chiral auxiliary of the complex with pyridine [32],... 

The effect of modifier structure was studied in the hydrogenation of EtPy in MeOH and in (DMF + water) Heinz et al. showed that a Pt-alumina catalyst modified with (5)-(-)-l-(l-naphthyl)ethylamine gave an ee of 82% in the hydrogenation of EtPy, whereas modification with Cnd under the same conditions gave only ee s of 73-75% but in the hydrogenation of the C=C bond in cinnamic acids ee values reached only 4-12%... 

Resolution of amines. The preparation of this acid and its use for resolution of a variety of amines were first disclosed in a patent. One advantage of this reagent is that it is water-insoluble and thus can be recovered in 91-947o vWd-An example of its use is the resolution of -(l-naphthyl)ethylamine to obtain the S-(—) isomer in 85-90% yield. ... 

The cyclopalladated complex (naphthyl)ethylamine-6, iV]-dipalladium has been used as a chiral template to promote the intramolecular [4 -h 2] Diels-Alder reaction between diphenyl-vinylphosphine and 1-phenyl-3,4-dimethylphosphole. Halide-bridged palladium(ii) dimers of orthopalladated (S)-(-h)-7V,7V-dimethyl-Q -methylbenzylamine and (naphthyl)ethyl]amine were reported by the same authors.Solution and solid-state structures were determined as well as reactions with 3,4-dimethyl-1-phenylphosphole and allyldiphenylphosphine carried out. 

Recently, a chiral monomer (a polymerizable L-valine derivative) instead of the commonly used achiral functional monomer has been employed for the preparation of a MIP-type CSP [189], In another attempt, a chiral monomer, (S)-(—)-N-methacryloyl-1-(1-naphthyl)ethylamine, and a racemic template were used for imprinting. This resulted in a MIP-type CSP, which showed enhanced enantioseparation capability for the racemate of the template (or = 1.40) compared to the corresponding MIP-type CSP which was obtained with the enantiomeric template (a = 1.18) (190]. 

S)-tert-Leudne ( R)-l-(a-naphthyl)ethylamine Sumichiral OA-4700 Sumitomo... 

S)-indoline-2-carboxylic acid and -l-(a-naphthyl) ethylamine urea linkage... 

Dawson et al. presented a study using different reagents, such as a-, 3-, and y-CDs, S-a-methylbenzylamine, (R)-A -3,5-dinitrobenzoyl-methylbenzylamine, (S)-1 -(1 -naphthyl)-ethylamine and (R)-2,2,2-trifluoro-l-(9-anthrylethanol) (R-TFAE), for enantiomeric evaluation of the dissolution of ketoprofen (Figure 6-7) formulations [8]. 

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