- Enantioselective synthesis of the tetracyclic core of platensimycin
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A concise preparative method for the tetracyclic core of platensimycin in an optically active form was developed through a nine-step sequence from p-anisaldehyde without the use of protecting groups. Georg Thieme Verlag Stuttgart · New York.
- Ueda, Yohei,Iwahashi, Kayoko,Iguchi, Kazuo,Ito, Hisanaka
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- Stereocontrolled Synthesis of (+)-Plagiogyrin A
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Plagiogyrin A (1) was first isolated from the fronds of Plagiogyria matsumureana. Structurally, it features an α-ketoaldehyde functional group in its hemiacetal form, fused in a cis-substituted lactone ring. We have successfully synthesized the skeleton o
- Shi, Yunlong,Pierce, Joshua G.
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p. 5308 - 5311
(2016/11/02)
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- Synthesis of versatile building blocks through asymmetric hydrogenation of functionalized itaconic acid mono-esters
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The rhodium-catalyzed asymmetric hydrogenation of several β-substituted itaconic acid monoesters, using a library of monodentate phosphoramidite and phosphite ligands is described. Two β-alkylsubstituted substrates were readily hydrogenated by the rhodium complex Rh(COD) 2BF4 in combination with (S)-PipPhos as a ligand resulting in ees of 99 %. In contrast, the corresponding more hindered β-arylsubstituted substrates did not exhibit acceptable enantioselectivities under these conditions. However, the use of a 48-membered ligand library led to the identification of several suitable ligands for these substrates, resulting in ees of 89-99%. The resulting optically active succinic acid derivatives are potentially useful building blocks for more elaborate compounds, because of the ability to differentiate between the carboxylic acid and the ester groups on either side of the molecule.
- Hekking, Koen F. W.,Lefort, Laurent,De Vries, Andre H. M.,Van Delft, Floris L.,Schoemaker, Hans E.,De Vries, Johannes G.,Rutjes, Floris P. J. T.
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experimental part
p. 85 - 94
(2009/04/07)
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- Catalytic asymmetric alkynylation and arylation of aldehydes by an H 8-binaphthyl-based amino alcohol ligand
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A novel chiral H8-1,1'-binaphthyl-based amino alcohol ligand (1Ra,2S,3R)-2 has been synthesized and applied in the direct nucleophilic addition of organozincs (alkynylzinc and arylzinc prepared in situ) to aldehydes, yielding the corresponding optically active propargylic alcohols and diarylmethanols in high yields and good to excellent enantioselectivities. For the asymmetric arylation reaction, one catalyst (1Ra,2S,3R)-2 can afford both enantiomers of many pharmaceutically interesting diarylmethanols by a proper combination of various arylzinc reagents and aldehydes.
- Ruan, Jiwu,Lu, Gui,Xu, Lijing,Li, Yue-Ming,Chan, Albert S. C.
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experimental part
p. 76 - 84
(2009/04/11)
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- Synthesis of Some Itaconates via Wittig Reaction
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The Wittig reaction of aromatic aldehydes with 1,2-bis-(ethoxycarbonyl) ethylidene triphenyl phosphorane (1) furnished oily mixtures of the two diastereomeric products (E) and (Z) (2).Alkaline hydrolysis of the diesters followed by fractional crystallizat
- Awad, William I.,Kandile, Nadia G.,Wassef, Wasfy N.,Mohamed, Mansoura I.
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p. 405 - 410
(2007/10/02)
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- Synthesis of Enol Lactones of 3-Aroyl-2-(thienylmethylene)-propionic Acids and their Conversion into the Corresponding 4-Arylbenzothiophene-6-carboxylic Acids
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Heterocyclic aldehydes such as 2-thiophenecarbaldehyde (1) condense with 3-aroylpropionic acids 2 or their sodium salts to give the enol lactones 3a-d of 3-aroyl-2-(2-thienylmethylene)propionic acids.Isomerization of 3a-d leads to the corresponding 4-aryl
- Guirguis, Nadia R.,Awad, Boshra M.,Saad, Hanaa A.
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p. 1003 - 1011
(2007/10/02)
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