- Desymmetrization of meso-Hydrobenzoin Using Chiral, Nucleophilic Phosphine Catalysts
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The desymmetrization of meso-hydrobenzoin is described using chiral phosphine catalysts 8b-d and 9-11. The best enantioselectivity at room temperature was obtained with the newly synthesized phospholane 8c and benzoic anhydride, but the reaction is very s
- Vedejs,Daugulis,Tuttle
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- Truncated Cinchona alkaloids as catalysts in enantioselective monobenzoylation of meso-1,2-diols
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Readily synthesised quincorine and quincoridine derived chiral diamines efficiently catalyse the asymmetric monobenzoylation of cyclic and acyclic meso-1,2-diols. The Royal Society of Chemistry.
- Kuendig, E. Peter,Enriquez Garcia, Alvaro,Lomberget, Thierry,Perez Garcia, Pablo,Romanens, Patrick
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supporting information; body text
p. 3519 - 3521
(2009/02/05)
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- Reduction of diesters of 1,2-diols. Regioselective C-O bond cleavage of the anionic forms
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The electrochemical reduction of benzoate diesters of glycols has been studied in acetonitrile and N,N-dimethylformamide as solvents. The reductions occur in two closely spaced one-electron steps, and it was found that the dianion diradicals decompose by one of two routes, depending on the substituents on the ethylene moiety: cleavage of two benzoates to produce alkene or formation of benzil by way of a postulated cyclic intermediate to produce also the dianion of the diol. These correspond to cleavage of the R-OC(O)Ar bonds and the RO-C(O)Ar bonds, respectively. When the radical formed by the former cleavage is a primary or secondary radical, the reaction is too slow to compete with the latter reaction that produces benzil. However, when that radical is either tertiary or benzylic, the former cleavage reaction is fast and no benzil is detected. The dianions of p-cyano- and p-nitrobenzoate esters are rather stable on the voltammetric time scale. However, the addition of lithium ions results in detectable formation of 4,4′-dicyanobenzil from four different p-cyanobenzoate diesters.
- Macias-Ruvalcaba, Norma A.,Moy, Cheryl L.,Zheng, Zi-Rong,Evans, Dennis H.
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p. 4829 - 4834
(2007/10/03)
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- Asymmetric acylation of meso-diols with benzoyl halide in the presence of a chiral diamine
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Nonenzymatic desymmetrization of cis-1,2-cyclohexanediol by the asymmetric acylation with achiral benzoyl chloride in the presence of a chiral diamine derived from (S)-proline took place to give monobenzoate in high optical yield.
- Oriyama, Takeshi,Imai, Keisuke,Hosoya, Takeshi,Sano, Tomohumi
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p. 397 - 400
(2007/10/03)
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- Highly efficient catalytic asymmetric acylation of meso-1,2-diols with benzoyl chloride in the presence of a chiral diamine combined with Et3N
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Catalytic asymmetric acylation of meso-1,2-diols has been successfully performed by the reaction with benzoyl chloride in the presence of 0.5 mol% of chiral diamine derived from (S)-proline combined with a stoichiometric amount of triethylamine to give th
- Oriyama, Takeshi,Imai, Keisuke,Sano, Tomohumi,Hosoya, Takeshi
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p. 3529 - 3532
(2007/10/03)
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- STUDIES ON THE SYNTHESIS OF HETEROCYCLIC COMPOUNDS. IX. SEPARATION OF DIASTEREOMERIC DIOL COMPOUNDS
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The separation of diastereomeric diols by transformation into the corresponding dioxastannolanes was carried out.The products are solid, stable and easily separable by fractional crystallization.By reaction of acids (or acyl halides) with the stannolanes the corresponding diols (or esters) were obtained in a high degree of purity.The structures of the compounds prepared were assigned on the basis of their analytical, physical and spectral data.
- Anchisi, Carlo,Maccioni, Antonio,Maccioni, Anna Maria,Podda, Gianni
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