Diethyl tartrate hydrogenation

Sinou and coworkers evaluated a range of enantiopure amino alcohols derived from tartaric acid for the ATH reduction of prochiral ketones. Various (2R,iR)-i-amino- and (alkylamino)-l,4-bis(benzyloxy)butan-2-ol were obtained from readily available (-I-)-diethyl tartrate. These enantiopure amino alcohols have been used with Ru(p-cymene)Cl2 or Ir(l) precursors as ligands in the hydrogen transfer reduction of various aryl alkyl ketones ee-values of up to 80% have been obtained using the ruthenium complex [93]. Using (2R,3R)-3-amino-l,4-bis(benzyloxy)butan-2-ol and (2R,3R)-3-(benzylamino)-l,4-bis(benzyloxy)butan-2-ol with [lr(cod)Cl]2 as precursor, the ATH of acetophenone resulted in a maximum yield of 72%, 30% ee, 3h, 25 °C in PrOH/KOH with the former, and 88% yield, 28% ee, 120 h with the latter. 

By a repetition of the above process, using the alkyl hydrogen tartrate, diethyl tartrate can be obtained, but the yield is poor. 

The Intermediate In this synthesis of disparlure, (Z)-2-tridecenol, Is obtained by hydrogenation of 2-trldecynol In the presence of a palladium catalyst poisoned with barium sulfate and quinoline. Oxidation of (Z)-2-tridecenol with tert-butyl hydroperoxlde/tItanium tetralsopropoxlde/D (-)-diethyl tartrate gives (2R, 3S)-epoxytrldecanol In enantiomeric excess reported to be as much as 98 percent after recrystalllzatlon. 

In this enantiodifferentiating photoreduction, the chiral amine plays two roles, as a chiral inductor and as an electron donor. Irradiation of 25 (Scheme 10) in a hexane slurry of unmodified NaY zeolite gave only the intramolecular hydrogen abstraction product 26. However, photolysis of 25 coimmobilized with ephedrine, pseudoephedrine, or norephedrine in NaY supercages afforded the reduction product 27 along with 26. It is clear that the immobilized amine plays the decisive role in the photoinduced electron-transfer reduction of 25, since 27 was not formed in unmodified or (— )-diethyl tartrate-modified zeolites. Consequently, the ee of obtained 27 was independent of the loading level of the chiral inductor. 

Hydrogen peroxide or t-butyl hydroperoxide may be used in the presence of a catalyst such as sodium tungstate(VI) or vanadyl acetylaceto-nate [ MeC0CH=C(0 )Me 2V0] for the epoxidation of allylic alcohols. The stereochemistry of the hydroxyl group has a profound effect on the stereochemistry of epoxidation. A system which has been applied to allylic alcohols, to make optically active epoxides, utilizes titanium(rV) isopropoxide, t-butyl hydroperoxide and either of the enantiomeric forms of diethyl tartrate. This system forms chiral epoxides of predictable stereochemistry. When the reactivity of epoxides is combined with the... 

Since before the turn of the century it has been known that the optical activity of some chiral compounds is solvent dependent (1 ). For example, in 1877 Landolt (2) reported that the specific rotations of (+)-camphor, (-)-nicotine, (+)-diethyl tartrate, and (-)-turpentine varied with solvent and concentration. In the last decade there has been renewed interest in this solvent dependence. A number of different types of organic compounds has been investigated and the results have been interpreted in terms of variations in conformer populations that have resulted from either the effect of the dielectric on coulombic interactions between dipolar groups in the molecule (3), or from hydrogen-bond interactions between the solvent and the chiral solute (k). 

When tartaric acid is heated with alcohol in the presence of hydrogen chloride, two hydrogen atoms are replaced by two ethyl groups, and diethyl tartrate is formed. This reaction shows that the acid contains two carboxyl groups. When diethyl tartrate is heated with acetic anhydride, two acetyl groups are introduced. The ester, therefore, contains two alcoholic hydroxyl groups. 

Phosphorus Compounds.—Treatment of the dioxaphospholen (635) with sulphur yields a mixture of the oxathiole (636) and fran -dibenzoylstilbene, PhCOCPh=CPhCOPh." 2-Phenyl-l,3,2-dioxaphospholan (637 R = Ph) dimerizes in solution to a ten-membered-ring compound, which was isolated as (638) by sulphurization." The cyclic thiophosphorous acid (639) exists in equilibrium with the betaine (640) in aqueous ethanol/ The spiro-compound (641), which contains a phosphorus-hydrogen bond, is formed by the action of (637 R = Cl) on diethyl tartrate. The phosphazene (642) spontaneously cyclizes to the spiro-compound (643). " Stable derivatives (645) and (646 R = Br) of five-co-ordinate phosphorus have been obtained by the action of bromine on the o-phenylene phosphite (644)/ The chlorine analogue (646 R Cl) reacts with 3,5-dimethylpyrazole to give the corresponding pyrazole derivative (646 R = 3,5-dimethylpyrazol-l-yl), which reversibly dimerizes to the zwitterion (647). ... 

A method for the electrochemical reduction of D-xylose to 2-deoxy-D-r/rr o-pentitol has been described. The homogeneous hydrogenation of sugars using tris-triphenylphosphine ruthenium chloride is improved in the presence of hydrogen chloride, which inhibits competitive decarbonylation of the sugar. L-(2,3)-Threitol is easily prepared from ( + )tartaric acid by lithium aluminium hydride reduction of the 2,3-0-isopropylidene derivative of diethyl tartrate, followed by acid hydrolysis of the resultant ketal. ... 

The original synthesis of diethyl teUnride by Wohler was carried out by treating potassium telluride with ethyl sulfate. The preparation of potassium telluride was rather inconvenient and involved the reduction of elemental tellurium by heating the element at red heat with potassium-hydrogen D-tartrate. An early report of Natta demonstrated that the treatment of aluminium telluride by alcohols or ethers at 250-300 °C is also a promising route to diorganyl tellurides. 

Tables IV-VIII describe the Pfeiffer Effect on the D.L-fNi(o-phen)o] with ( +) -tartaric acid, sodium hydrogen (+) tartrate, the diethyl-2-methoxy-...

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