1.2- Diphenylethylene-1,2-diamine

Chiral salen ligands are diimines of salicylaldehydes with chiral diamines, usually cyclohexane-1,2-diamine (salen Hgands 1) or 1,2-diphenylethylene-diamine (salen ligands 2). The most widely used salen ligand in homogeneous catalysis is probably Jacobsen s ligand (la. Fig. 2), which is commercially available and hence has been used as reference to compare the results of im-... 

Triethyl orthoformate, condensation with N,N -diphenylethylene-diamine, 47, 14... 

The preparation of other stereospecific hydrogenation catalysts such as ruthenium dichloride((S)-(6,6 -dimethoxybiphenyl-2,2 -diyl)bis[bis(3,5-dimethyl-xylene)((R,R)-2-diphenylethylene-diamine)] is provided (2). Other suitable ligands such as l,2-bis(2,5-dimethylphospholano)benzene are described (3). 

The brush-type of CSP was introduced by Pirkle who was one of the pioneers of modern enantioselective liquid chromatography [55]. The most frequently used 7i-acceptor phases are derived from the amino acids phenylglycine (DNBPG) (Fig. 6.8) or leucine (DNBLeu) covalently or ionically bonded to 3-aminopropyl silica gel [56, 57]. These CSPs are commercially available for analytical or preparative separation of enantiomers. Further CSPs based on amino acid or amine chiral selectors such as valine, phenylalanine, tyrosine [58] and l,2-tr s-diaminocyclohexane (DACH-DNB phase) [59] and 1,2-traus-diphenylethylene diamine (ULMO phase) [60] were also developed (Fig. 6.8). These CSPs have been applied for the preparative separation of the enantiomers of a few racemic compounds, but the number of reported preparative applications has remained very limited over the last 10 years. 

As mentioned earlier, in fluorimetric detection, the amines may be monitored either by natural fluorescence or after derivatization reaction with either 1,2-diphenylethylene-diamine (DPE), trihydroxyindole o-phthalaldehyde (OPA) or fluor-... 

Noyori was subsequently able to show that triethylamine salts of formic acid (TEAF) could be used to reduce ketones to alcohols and imines to amines with high enantioselectivities [4]. The byproduct of this reaction is carbon dioxide gas and this prevents the possibility of the reverse reaction. Strangely, aminoalcohol ligands are poor in this reaction, whilst unsymmetrical 1,2-diamines have proven very effective. A particularly effective ligand is mono-N-tosyl-l,2-diphenylethylene-diamine. 

D. Resolution of the dl-diamine (R,R)-(+)-N,N -Dimethyl-1,2-diphenylethylene-diamine and (S,S)-(-)-N,N -Dimethyt-1,2-diphenylethylenediamine. A 1-L, round-bottomed flask, equipped with a magnetic stirring bar and a water condenser, is charged with pure dl-diamine (12 g, 0.05 mol), natural L-(+)-tartaric acid (7.1 g, 0.05 mol) (Note 14) and absolute ethanol (350 mL). The heterogeneous mixture is brought to reflux and the precipitate dissolves completely (Note 15). After 30 min the solution is allowed to cool to room temperature and stand overnight (17 hr). The precipitate is collected by filtration and washed with ethanol (2 x 50 mL). The salt is added to a mixture of aqueous 35% (w/w) NaOH (30 mL), demineralized water (100 mL) and Et20 (100 mL). The solution is stirred for 30 min, and the phases are separated. The... 

Reagents i, MejSO-DCC-ClgHCCOjH ii, iV,A -diphenylethylene diamine iii, Resin(H+) iv, CgH -azeotrope v, (—)-a-pinene-9-borabicyclo[3,3,llnonane... 

Diphenylpiperazine can be titrated in acetic anhydride with perchloric acid. The titration curve resulting from plotting millivolts vs. volume of titrant gives two equal and well-defined inflection points. Diphenylpiper-azine is a by-product in the synthesis of diphenylethylene-diamine and may be determined in the presence of the same by acetylation and titration in acetic acid with perchloric acid. It may be identified by separation and titration, obtaining the very characteristic curve in acetic anhydride. Interferences from other tertiary amines and aniline are dealt with in these determinations of diphenylpiperazine. 

Deng and coworkers synthesized the water-soluble chiral o,o -disulfonated-N-tosyl-l,2-diphenylethylene diamine 22 [82] and o,o -aminated-N-tosyl-l,2-diphenylethylenediamine 23 [83] and showed them to be effective for rhodium-. 

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