- Asymmetric Catalytic Reduction of meso-Imides
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A thiazazincolidine complex, 1, was shown to be an excellent catalyst for enantioselective reduction with bis(2,6-dimethylphenoxy)borane (BDMPB) of meso N-phenylimides in high ee to the corresponding hydroxy lactams, which were eventually converted to the corresponding lactones of high optical purity.
- Kang, Jahyo,Lee, Jun Won,Kim, Joo In,Pyun, Chongsuh
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- Highly enantioselective reduction of meso-1,2-dicarboxylic anhydrides
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Optically active lactones (2a-2g) were synthesized by highly enantioselective reduction of readily available meso-1,2-dicarboxylic anhydrides (1a-1g) using lithium aluminum hydride-ethanol-1,1'-bi-2-naphthol complex (BINAL-H).
- Matsuki,Inoue,Takeda
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- Catalytic asymmetric oxidative lactonizations of meso-diols using a chiral iridium complex
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A chiral amino alcohol/Ir complex catalyzes the asymmetric oxidative lactonizations of meso-diols to give the corresponding lactones in up to 81% ee.
- Suzuki, Takeyuki,Morita, Kenji,Matsuo, Yoshimi,Hiroi, Kunio
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p. 2003 - 2006
(2007/10/03)
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- Preparation of a Promising Cyclobutanone Chiral Building Block: Its Stereochemistry and Utilization
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A cyclobutanone possessing a bicyclo[2.2.1]heptene framework {endo-tricyclo[4.2.1.02,5]non-7-en-3-one} has been prepared in both enantiomeric forms employing lipase-mediated kinetic resolution as the key step. To determine the absolute configuration, as well as to demonstrate the synthetic potential, both enantiomers of the cyclobutanone obtained have been transformed enantioconvergently into the key intermediate of the sesquiterpene (+)-β-santalene and the iridoid monoterpene (-)-boschnialactone.
- Taniguchi, Takahiko,Goto, Yasuo,Ogasawara, Kunio
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p. 707 - 709
(2007/10/03)
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- Enantioselective reduction of meso-cyclic-1,2-dicarboxylic anhydrides and 1,2-dicarboximides: Asymmetric synthesis of bicyclic lactones and hydroxylactams
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Chiral bicyclic lactones (3,8,9) and bicyclic hydroxylactams (10-13) were synthesized by highly enantioselective reduction of meso-cyclic-1,2- dicarboxylic anhydrides (1, 4) and meso-cyclic-1,2-dicarboximides (2) with lithium aluminum hydride (LiAlH4)-alcohol(ROH)-(R)- or (S)-1,1'-bi-2- naphthol complex [(R)- or (S)-BINAL-H(ROH)]. Treatment of the hydroxylactams (10-13) with triethylsilane (Et3SiH) and trifluoroacetic acid (CF3CO2H) gave chiral bicyclic lactams (14, 15) in quantitative yields. Removal of the N-4-methoxyphenyl group of the lactams (14, 15) with cerium(IV) ammonium nitrate (CAN) proceeded smoothly to give the corresponding N-unsubstituted lactams (16, 17) in high optical purity.
- Matsuki,Inoue,Ishida,Takeda,Nakagawa,Hino
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- Synthesis and Asymmetric Diels-Alder Reaction of Dimethyl ('d-Isoborneol-10-sulphinyl')maleate: Novel Route to Key Intermediates for Synthesis of Some Carbocyclic Nucleosides and Terpenoids
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The chiral sulphoxide 1 was synthesized from 10-mercaptoisoborneol via diastereoselective oxidation.The dienophile 1 reacted with cyclopentadiene in the presence of a Lewis acid to give the adducts 7 and 8 with high diastereoselectivity (ca. 100percent).D
- Arai, Yoshitsugu,Hayashi, Kazuya,Matsui, Makoto,Koizumi, Toru,Shiro, Motoo,Kuriyama, Kaoru
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p. 1709 - 1716
(2007/10/02)
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- An Enantiodivergent Synthesis of Fused Bicycloheptane Lactones via an Asymmetric Diels-Alder Reaction
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An enantiodivergent synthesis of the bicycloheptane lactone (2) is described, by regioselective reduction of the Diels-Alder adducts (3) and (4) with di-isobutylaluminium hydride followed by reductive elimination of the chiral auxiliary, 10-mercaptoisoborneol (9) through reaction with samarium(II) iodide.
- Arai, Yoshitsugu,Matsui, Makoto,Koizumi, Toru
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p. 1233 - 1234
(2007/10/02)
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- PREPARATION OF ENANTIOMERICALLY PURE 3-ENDO-SULFONYLMETHYL SUBSTITUTED BICYCLOHEPTANE-2-ENDO-CARBOXYLIC ACIDS
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Both enantiomers of title acids 5 were synthesized from mono-ester rac-1.An alternative approach via PLE catalyzed hydrolysis of a meso diester is described too.
- Metz, P.
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p. 7311 - 7316
(2007/10/02)
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- Enantiodivergent Route to Both Enantiomers of β-Santalene and epi-β-Santalene from a Single Chiral Template
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An enantiodivergent route to both enantiomers of β-santalene, constituents of East Indian sandalwood oil, has been developed using a single chiral template.
- Takano, Seiichi,Inomata, Kohei,Kurotaki, Ayako,Ohkawa, Takehiko,Ogasawara, Kunio
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p. 1720 - 1722
(2007/10/02)
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