- Asymmetric ring-opening of cyclohexene oxide with mercaptan (thiophenols) catalyzed by chiral Schiff base/Ti(OPr-i)4 or (-)-(S)-binaphthol/Ti(OPr-i)4
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New chiral Schiff base ligands 1-4 were synthesized starting from (+)-camphor and (+)-1-(4-nitrophenyl)-2-amino-1,3-propanediol, and their application in asymmetric ring-opening of cyclohexene oxide using mercaptan (thiophenols) as nucleophiles was investigated. The aymmetric ring-opening of cylohexene oxide catalyzed respectively by chiral Schiff bases 1-4/Ti(OPr-i)4 and (-)-(S)-1,1′-binaphthalene-2,2′-diol 5/Ti(OPr-i)4 complex afforded the corresponding chiral β-hydroxysulfides 6-10 in lower to good yield with lower to moderate ee values. Moreover, the using of (-)-(S)-1,1′-binaphthalene-2,2′-diol as ligand led to better chiral induction effect.
- Zhou, Zhenghong,Li, Zhaoming,Li, Kangying,Yang, Zhuohong,Zhao, Guofeng,Wang, Lixin,Zhou, Qilin,Tang, Chuchi
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- An unexpected reaction of camphor with sodium metal
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Reaction of camphor with sodium metal at elevated temperature in refluxing THF or toluene, furnishes an unexpected product. The product has been identified by spectral analysis and its structure confirmed by single crystal X-ray diffraction study. A preliminary mechanistic explanation has been suggested to explain this reaction.
- Khanvilkar, Aditya N.,Gupta, Riddhi,Bedekar, Ashutosh V.
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p. 1327 - 1331
(2016/02/23)
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- An unexpected reaction of camphor with sodium metal
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Reaction of camphor with sodium metal at elevated temperature in refluxing THF or toluene, furnishes an unexpected product. The product has been identified by spectral analysis and its structure confirmed by single crystal X-ray diffraction study. A preliminary mechanistic explanation has been suggested to explain this reaction.
- Khanvilkar, Aditya N.,Gupta, Riddhi,Bedekar, Ashutosh V.
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p. 1327 - 1331
(2015/11/10)
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- Synthesis and characterization of Ru(II) and Ir(III) complexes that bear camphoric 1,3-diamine ligands
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Two rigid N-monosulfonylated 1,3-diamine ligands have been prepared starting from commercially available d-camphor through three steps. Their reactions with [Ru(η6-arene)(μ-Cl)Cl]2 (arene = p-cymene or C6H5CO2Et) or [Ir(η 5-C5Me5)(μ-Cl)Cl]2 afforded five new complexes. The structures of one monosulfonamide 1,3-diamine ligand and three organometallic complexes were confirmed by X-ray crystallography.
- Yu, Jun-Lai,Guo, Rong,Wang, Hui,Li, Zhan-Ting,Zhang, Dan-Wei
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- Synthesis of 1,11,11-trimethyl-3,6-diazotricyclo [6.2.1.0 2,7]undeca-2,6-diene and 1,15,15-trimethyl-3,10-diazotetracyclo[10.2. 1.02,11.04,9]pentadeca-2,4(9),5,7,10-pentaene from camphoroquinone enantiomers
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Optically active camphordihydro-2,3-pyrazine and camphorquinoxaline were prepared from camphoroquinone enantiomers. It was shown that (1S,4R)-(+)-camphoroquinone was formed by oxidation of (1S,3R, 4R)-(-)-3-bromocamphor and (1R,4S)-(-)-camphoroquinone from (1R,3S, 4S)-(+)-3-bromocamphor, respectively. Camphor anhydride was a side product (6-10%) of the reaction. Springer Science+Business Media, Inc. 2007.
- Adamenko,Frolova,Panteleeva,Kuchin
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- Asymmetric trimethylsilylcyanation of aldehydes catalyzed by chiral schiff base-Ti(OiPr)4 complex
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A new chiral Schiff base 4 was synthesized, which was found to be efficient catalyst for the enantioselective silylcyanation of aldehydes. The enantioselectivities of 25.1-72.7% were obtained by using the chiral Schiff base-Ti(OiPr)4 complex.
- Yang,Zhou,Tang
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p. 3031 - 3036
(2007/10/03)
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- Process for making an optically active mixture of an n-acyl-amino acid or ester containing at least two chiral centers
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In the process of hydrocarboxylating an α-enamide with CO and H2O or an organic hydroxyl compound to produce an N-acyl-α-amino acid or ester, respectively, the improvement comprising using as the α-enamide reactant, an α-enamide which has a chiral center that is essentially all L or D, thereby producing a reaction mixture containing diastereomeric N-acyl-α-amino acids or esters having two chiral centers, said mixture having essentially no enantiomeric pairs.
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- Process for making an optically active mixture of an N-acyl-amino acid or ester containing at least two chiral centers
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In the process of hydrocarboxylating an α-enamide with CO and H2 O or an organic hydroxyl compound to produce an N-acyl-α-amino acid or ester, respectively, the improvement comprising using as the α-enamide reactant, an α-enamide which has a chiral center that is essentially all L or D, thereby producing a reaction mixture containing diastereomeric N-acyl-α-amino acids or esters having two chiral centers, said mixture having essentially no enantiomeric pairs.
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- Carotenoids and Related Compounds. Part 37. Stereochemistry and Synthesis of Capsorubin
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The two oxygen substitutents in the end groups of capsorubin were shown to be trans to one another by synthesis of optically inactive forms of the carotenoid, and of the isomers which have the corresponding cis-structure.The 3S,5R,3'S,5'R configuration thus established for the natural carotenoid was confirmed by synthesis of this stereoisomer from (+)-camphor.Cryptocapsin has the 3'S,5'R configuration, and the racemic form has been synthesised.Capsanthin has the 3R,3'S,5'R configuration.
- Bowden, Roy D.,Cooper, Robin D. G.,Harris, C. John,Moss, Gerard P.,Weedon, Basil C. L.,Jackman, Lloyd M.
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p. 1465 - 1474
(2007/10/02)
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- CHEMICAL TRANSFORMATION OF TERPENOIDS. I. SYNTHESES OF (3S)-1-VINYL-, (3S)-1-HYDROXYPROPENYL-, AND (3S)-1-EPOXYETHYL-1,2,2-TRIMETHYLCYCLOPENTANE DERIVATIVES FROM d-CAMPHOR VIA d-CAMPHORIC ACID
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As part of a series of studies on the transformation of terpenoids, four 1,2,2-trimethylcyclopentane derivatives, i.e., (+)-(1S,3S)-3-acetoxymethyl-1,2,2-trimethyl-1-vinylcyclopentane (5), (+)-(1S,3S)-3-acetoxymethyl-1-(3'-hydroxypropenyl)-1,2,2-trimethylcyclopentane (7), (+)-(1R,3S,1'S)-3-acetoxymethyl-1-(1',2'-epoxyethyl)-1,2,2-trimethylcyclopentane (8), and (+)-(1R,3S,1'R)-3-acetoxymethyl-1-(1',2'-epoxyethyl)-1,2,2-trimethylcyclopentane (9), were synthesized from d-camphor (1) via d-camphoric acid (2).All four compounds (5,7,8,9) retain the C-4 configuration of d-camphor at their C-3 positions.Keywords: - d-camphor; d-camphoric acid; 1-vinyl-1,2,2-trimethylcyclopentane; 1-hydroxypropenyl-1,2,2-trimethylcyclopentane; 1-epoxyethyl-1,2,2-trimethylcyclopentane; Horeau's method
- Kitagawa, Isao,Shibuya, Hirotaka,Fujioka, Hiromichi,Kajiwara, Akiharu,Yamamoto, Yoshio,et al.
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p. 2540 - 2547
(2007/10/02)
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- SUCCESSIVE METHYL MIGRATIONS OCCURING IN THE ACID TREATMENT OF 1-EPOXYETHYL-1,2,2-TRIMETHYL-CYCLOPENTANE DERIVATIVE
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Acid treatment of (1R,3S,1'S)-1-(1',2'-epoxyethyl)-1,2,2-trimethyl-3-acetoxymethyl-cyclopentane (6) has been shown to yield three products (8, 9, 10), among which 8 and 9 are 1-oxa-bicyclooctane derivatives formed via successive methyl migrations followed by an oxorane ring closure.
- Kitagawa, Isao,Shibuya, Hirotaka,Fujioka, Hiromichi,Yamamoto, Yoshio,Kajiwara, Akiharu,et al.
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p. 1963 - 1966
(2007/10/02)
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