1.2- diphenylethane-1,2-diamine

Included in this class of olefins is ( )-stilbene (entry 20), which throughout studies of AD has usually been the olefin dihydroxylated with the highest degree of enantioselectivity. Availability of (R,R) or (.5,5)-1,2-diphenyl-1,2-ethanediol (also referred to as stilbenediol or dihydrobenzoin) with high enantiomeric purities has led to reports of a number of applications, including incorporation into chiral dioxaphospholanes [50], chiral boronates [51], chiral ketene acetals [52], chiral crown ethers [53], and conversion into 1,2-diphenylethane-1,2-diamines [54]. Dihydroxylation of the substituted rran.r-stilbene 46 with Os04/NMO and DHQD-CLB gives the i ,/ -diol 47 with 82% ee in 88% yield [55]. 

A CSP based on the analogues 3,5-dinitrobenzoylated 1,2-diphenylethane-1,2-diamine (DNB-DPEDA) (see Fig. 9.26a) [349-353] has been commercialized by Regis under the tradename Ulmo. This CSP has proven to be excellent for the direct separation of aryl alcohol enantiomers without derivatization (see Fig. 9.26b) [349,351]. This improved Pirkle-concept CSP, that contains also ir-acidic as well as moderate n-basic aromatic binding sites, nicely resolved a wide variety of chiral drugs [350] and compounds of pharmaceutical interest [352]. 

Michael addition of acetone to nitroolefins is catalysed by a simple thiophos-phoramide derived from 1,2-diphenylethane-1,2-diamine, /ra x-Ph-CH(NH2)-CH(Ph)-NH-P(=S)Ph2, in up to 99% yield and ee at room temperature. ... 

In 2001, Tomioka et al. investigated several seven-membered cycloalkanones 364 and 365 bearing 1,2-diphenylethane-1,2-diamine and cyclohexane-l,2-diamine backbones [249,250], However, only 30% ee could be achieved for the epoxidation of irans-stilbene with ketone 364b, while the tricychc ketone 366 and bicyclic ketone 367 gave 64% ee and 57% ee, repectively [251]. 

In 2003, Sigman et al. reported the use of a chiral carbene ligand in conjunction with the chiral base (-)-sparteine in the palladium(II) catalyzed oxidative kinetic resolution of secondary alcohols [26]. The dimeric palladium complexes 51a-b used in this reaction were obtained in two steps from N,N -diaryl chiral imidazolinium salts derived from (S, S) or (R,R) diphenylethane diamine (Scheme 28). The carbenes were generated by deprotonation of the salts with t-BuOK in THF and reacted in situ with dimeric palladium al-lyl chloride. The intermediate NHC - Pd(allyl)Cl complexes 52 are air-stable and were isolated in 92-95% yield after silica gel chromatography. Two diaster corners in a ratio of approximately 2 1 are present in solution (CDCI3). 

The molecular imprinting method can be used to synthesize enantioselective solid materials for asymmetric organic synthesis. The first attempt to use a metal complex with an attached chiral ligand as a template was attempted by Lemaire [52]. The Rh complex, ((15,25)-V,V -dimethyl-l,2-diphenylethane diamine)-[Rh(CgHj2)Cl]2 coordinated with optically pure l-(5)-phenylethoxide or phenylethoxide (Rh 1-phenylethanolate) (template) was polymerized in the presence of isocyanate, and the polyurea-supported Rh complex is reacted with isopropanol to extract the template from the polymer backbone. They reported the influence of molecular imprinting on catalytic performance (conversion and enantiomeric excess) for the asymmetric transfer hydrogenation (Table 22.2). The imprinted polymer exhibited higher enantioselectivity compared to a nonimprinted... 

Uray, G., Maier, N.M. Diphenylethane-diamine (DPEDA) derivatives as chiral selectors. VI. Enantioseparation ofunder-ivatized aryl substituted carboxylic acids on four differently linked N-3,5-dinitro-benzoyl-DPEDA derived CSPs, Enantiomer, 1996,1, 211-217. 

Maier, N. M., Uray, G. Diphenylethane-diamine (DPEDA) as chiral selector ... 

A Typical procedure for imprinted polymerised rhodium complex synthesis is in a round bottom flask under inert dry atmosphere of argon, 750mg (3.12mmol) of (1S,2S)-N,N-dimethyl-l,2-diphenylethane diamine 8 are dissolved in 4 ml of dichloromethane freshly distilled from P2O5 78 mg (0.32mmol) of catalytic precursor ([Rh(C8Hi2)Cl]2) are added and the solution stirred. 

Polymerised preformed [(N,N -dimethyl-l,2-diphenylethane diamine)2Rh] complex allows us to obtain enantioselective material. We have then shown that it is possible to imprint an optically pure template into the rhodium-organic matrix and to use the heterogeneous catalyst in asymmetric catalysis with an obvious template effect. The study of yield versus conversion graphs has shown that the mechanism occurs via two parallel reactions on the same site without any inter-conversion of the final products. Adjusting the cross-linker ratio at 50/50 allows us to find a compromise between activity and selectivity. Phenyl ethyl ketone (propiophenone) was reduced quantitatively in 2 days to (R)-l-phenyl propanol with 7tf% enantiomeric excess We have then shown that the imprinting effect is obvious for molecules related in structure to the template (propiophenone, 4 -trifluoromethyl acetophenone). It is not efficient if the structure of the substrate is too different to that of the template. 

Bis[(lS,2S)-N,N -dimethyl-1,2-diphenylethane diamine]-l-(R)-phenylethoxy-Rh(I) complex Diisocyanate triisocyanate CH2Cl2... 

Locatelli et al. [13] investigated the hydride transfer reduction of prochiral ketones using a rhodium based catalyst on a polyurea support. The homogeneous reduction of acetophenone using a rhodium catalyst with two equivalents of (1 S, 2 5 )-iV,iV -dimethyl-l,2-diphenylethane diamine was conducted to establish an appropriate comparison for the imprinting studies. This control reaction resulted in formation of 1-(J ) -phenyl ethanol with 67% ee (Scheme 6). The low enantioselectivity was attributed to a poor coordination sphere surrounding the metal center. The selectivity from the hydride transfer is proposed to arise from the approach of the substrate to the metal center, as shown in Scheme 7. The metal... 

Tliere is only one report concerning the reaction of A -(l-chloroalkyl)-pyridinium chlorides with secondary diamines (92BSB233). 2-Substituted 1,3-dimethyl- and 1,3-diphenyl-imidazolidines 79 have been prepared (75-95% yields) starting from either -dimethyl- or A, A -diphenylethane-1,2-diamines, respectively (Scheme 25). Reactions are particularly fast for the preparation of the 1,3-dimethylimidazolidines. Reaction times as short as 5 min have been claimed. 

Abbreviations JV,JV -Me2en, 1,2-bis(methylamino)ethane V,iV-Me2en, JV,JV-dimethyl(ethane-l,2-diamine) m-stien, l,2-diphenylethane-l,2-di N,N -Et2en, l,2-bis(ethyiamino)ethane 2-Meim, 2-methyhmidazole. 

Hydrogen fluoride can be eliminated from rV./V-difluoroalkylamines.104-107 N,N,N, N -Tetrafluoro-1.2-diphenylethane-l,2-diamine (3) on dehydrofluorination gives AfA -difluoro-1,2-diphenylethane-l. 2-diimine (4).104... 

Evaporation of the mother liquor and treatment of the residue under similar experimental conditions afforded ( )-(—)-34 in a yield of 57% with an optical purity of 62%. Optically active threo-1,2-diamino-1,2-diphenylethane was also an effective diamine for the optical resolution of racemic 34 that was obtained in a yield of 78% with an optical purity of 92% [70]. As previously described, the optical resolution of racemic trans-1,2-cyclohexanediol could be performed under similar experimental conditions [27]. Notably, this procedure was found effective also for the optical resolution of hydroxy oximes. Thus, when equimolar amounts of racemic ( )-l,2-diphenyl-2-(hydroxyimino)ethanol (50) and (R,R)-29 were added to benzene and crystallized, (7 )-(—)-( )-50 was recovered in a yield of 56 % based on the enantiomer in the racemate (Scheme 24) [27]. 

The efficient transmetalation of allylic stannanes to allylboron reagents has generated an attractive methodology for asymmetric allylation. Corey and coworkers first described the use of enantiomers of bromoborane 228 (Scheme 5.2.51) for mild and quantitative transmetalation of allylstannane to yield the allylboron reagent 229. i The asymmetry in the bis-toluenesulfonamide of 228 is derived from l,2-diamino-l,2-diphenylethane, and both antipodes are readily available in high optical purity, by resolution of the starting diamines producing (R,R)- and (5, 5 )- Stein chiral auxiliaries in transmetalation product 229. 

FIG URE 6.13 Radial pentagon for classical resolution of 1,2-diphenylethane-l,2-diamine [11]. Note that the yield of the diastereomeric salt in the first step is less than 50%. 

Ru(II) arene and Rh(III) pentamethylcyclopentadienyl complexes with dinitrogen donor ligands related to Noyori s diamine AT-tosyl-l,2-diphenylethane-1,2-diamine (TsDPEN) or amino alcohols are by far the most employed... 

This methodology has also been employed for the preparation of tetradentate ligands by exchanging the primary amines for C2-symmetric primary diamines (eq 4). For example, from (/ ,/ -1,2-diamino-1,2-diphenylethane, diastereomeric ligand B was obtained in 84% yield. These aromatic amines are sufficiently reactive to open the aziridine ring. Due to steric hindrance, no further reaction of the secondary amine moieties with (5)-A -trifluoromethylsulfonyl-2-isopropylaziridine was observed. This tetradentate ligand was inferior to his(sulfonamides) as catalyst... 

Aminophosphines have received less attention as ligands than phosphites, but nevertheless, a number of compounds in this group have been prepared as ligands for studies of catalytic reactions. With one exception, all the ligands were prepared from diphenylchlorophosphine and amine. The exception was that prepared from phosphorus tribromide. Ligands included chiral iV,iV -dimethyl-l,2-diphenylethane-l,2-diamine derivatives... 

Kelly AM, Bull SD, James TD. Simple chiral derivatisation protocols for NMR analysis of the enantiopmity of 1,2-diphenylethane-l,2-diamine and N-Boc-cyclohexane-1, 2-diamine. Tetrahedron Asymm. 2008 19 489 94. 

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