- P,S ligands for the asymmetric construction of quaternary stereocenters in palladium-catalyzed decarboxylative [4+2] cycloadditions
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A new hybrid P,S ligand was exploited by combining a chiral β-amino sulfide and a simple diphenyl phosphite. The resultant ligand performs extremely well in a palladium-catalyzed asymmetric decarboxylative [4+2] cycloaddition reaction, thus generating mul
- Wei, Yi,Lu, Liang-Qiu,Li, Tian-Ren,Feng, Bin,Wang, Qiang,Xiao, Wen-Jing,Alper, Howard
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supporting information
p. 2200 - 2204
(2016/02/18)
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- Catalytic enantioselective α-tosyloxylation of ketones using iodoaryloxazoline catalysts: Insights on the stereoinduction process
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A family of iodooxazoline catalysts was developed to promote the iodine(III)-mediated α-tosyloxylation of ketone derivatives. The α-tosyloxy ketones produced are polyvalent chiral synthons. Through this study, we have unearthed a unique mode of stereoinduction from the chiral oxazoline moiety, where the stereogenic center alpha to the oxazoline oxygen atom is significant. Computational chemistry was used to rationalize the stereoinduction process. The catalysts presented promote currently among the best levels of activity and selectivity for this transformation. Evaluation of the scope of the reaction is presented.
- Guilbault, Audrey-Anne,Basdevant, Benoit,Wanie, Vincent,Legault, Claude Y.
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p. 11283 - 11295
(2013/02/23)
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- PYRIDO PYRIMIDINES
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Compounds of formula and pharmaceutically acceptable salts thereof are described, as well as the pharmaceutical compositions containing said compounds and their pharmaceutically acceptable salts, and the use of said compounds and pharmaceutical compositions for the treatment, control or amelioration of proliferative diseases, including cancer, Down syndrome or early onset Alzheimer's disease.
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Page/Page column 15
(2012/07/28)
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- A stereo-controlled synthesis of 2,4-dimethyl-4-hydroxy-16- phenylhexadecanoic acid 1,4-lactone and its PPAR activities
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A novel class of natural PPAR agonists, 2,4-dimethyl-4-hydroxy-16- phenylhexadecanoic acid 1,4-lactone (1), were discovered in marine natural product libraries. The synthesis of 1 was accomplished starting from vinylmethyl ketone. Ring formation of the α,γ dialkyl γ-lactone was achieved via the stereo-controlled reaction of a ketyl radical anion with a chiral methacrylate. In the PPAR agonistic assay, the most potent of the four stereoisomers had EC50 values of 12 μM for mPPARα, 9 μM for mPPARδ and >100 μM for mPPARγ.
- Ko, Jaeyoung,Hwang, Hoosang,Chin, Jungwook,Hahn, Dongyup,Lee, Jaehwan,Yang, Inho,Shin, Kyoungjin,Ham, Jungyeob,Kang, Heonjoong
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scheme or table
p. 6017 - 6019
(2010/11/17)
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- Asymmetric oxidations of electron-poor alkenes promoted by the β-amino alcohol/TBHP system
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The asymmetric oxyfunctionalization of alkenes is a fundamental process in synthetic organic chemistry. In this contribution, we review our findings on the enantioselective organocatalyzed oxidation of electron-poor alkenes. Readily or commercially available β-amino alcohols displayed catalytic activity in the asymmetric epoxidation of α,β-enones and β-peroxidation of nitroalkenes with tert-butyl hydroperoxide (TBHP) as the oxidant. The corresponding epoxides and peroxides were isolated in good to high yield and enantioselectivity. Georg Thieme Verlag Stuttgart.
- Russo, Alessio,Lattanzi, Alessandra
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scheme or table
p. 1551 - 1556
(2009/12/06)
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- Highly efficient recyclable CoIII-salen complexes in the catalyzed asymmetric aminolytic kinetic resolution of aryloxy/terminal epoxides for the simultaneous production of N-protected 1,2-amino alcohols and the corresponding epoxides in high op
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Chiral CoIII-salen complexes 1-6 bearing different substituents at the 3,3′- and 5,5′-positions of the salen unit, namely H, tBu, morpholmomethyl, and piperidinomethyl, have been synthesized. These complexes were used as catalysts in an environ
- Kureshy, Rukhsana I.,Prathap, K. Jeya,Agrawal, Santosh,Kumar, Manish,Khan, Noor-Ul H.,Abdi, Sayed H. R.,Bajaj, Hari C.
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supporting information; experimental part
p. 2863 - 2871
(2009/09/29)
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- Enantioselective synthesis of O-methoxycarbonyl cyanohydrins: Chiral building blocks generated by bifunctional catalysis with BINOLAM-AlCl
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(R)- or (S)-BINOLAM-AlCl, generated in situ, work as bifunctional catalysts in promoting the enantioselective cyanoalkoxycarbonylation of aldehydes. The reaction is wide in scope and the mechanistic evidence gathered suggests the intervention of an indirect process involving enantioselective hydrocyanation by HCN, followed by O-alkoxycarbonylation. The resultant O-alkoxycarbonyl cyanohydrins are shown to be important chiral building blocks for synthesis. Chemoselective hydrolysis can thus be directed either to provide enantioenriched β-hydroxy esters, or acids, or instead to give O-methoxycarbonyl β-hydroxy acids, esters, or amides. In addition, the enantiopure cyanocarbonates can be converted into β-amino alcohols by reduction with lithiumaluminium hydride. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
- Baeza, Alejandro,Casas, Jesús,Nájera, Carmen,Sansano, José M.,Saá, José M.
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p. 1949 - 1958
(2007/10/03)
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- Binolam-AlCl: A two-centre catalyst for the synthesis of enantioenriched cyanohydrin O-phosphates
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The enantioselective synthesis of cyanohydrin O-phosphates by using in situ generated bifunctional catalysts (R)- or (S)-3,3′-bis(diethylaminomethyl) -1, 1′-binaphthol-aluminium chloride (binolam-AlCl) is reported. The reaction, which can be described as an overall cyano-O-phosphorylation of aldehydes, has a wide scope and applicability. Evidence is also provided, including ab initio and DFT calculations, in support of supported by the Lewis acid/Bronsted base (LABB) dual role of the catalyst in inducing first the key enantioselective hydrocyanation, which is then followed by O-phosphorylation. A brief screening of the synthetic usefulness of the resulting cyanohydrin O-phosphates unveiles some interesting applications. Among them, chemoselective hydrolysis, reduction and palladium-catalysed nucleophilic allyl substitution, thereby leading to enantiomerically enriched α-O-phosphorylated α-hydroxy esters, β-amino alcohols and γ-cyanoallyl alcohols, respectively. Naturally occurring (-)-tembamide and (-)-aegeline are synthesised accordingly.
- Baeza, Alcjandro,Najera, Carmen,Sansano, Jose M.,Saa, Jose M.
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p. 3849 - 3862
(2007/10/03)
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- NOVEL COMPOUNDS
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There are provided novel compounds of formula (I) wherein R1, R2, R3, R10, M, Q, T, U, Y, V and W are as defined in the specification and pharmaceutically acceptable salts thereof; together with processes for th
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- Synthetic applicability and in situ recycling of a B-methoxy oxazaborolidine catalyst derived from cis-1-amino-indan-2-ol
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A procedure is described that greatly simplifies the use of an oxazaborolidine catalyst derived from (1R,2S) cis-1-amino-indan-2-ol. This B-OMe catalyst has been employed in the asymmetric reduction of a number of structurally diverse prochiral ketones, in particular the reduction of α-amino acetophenone and its derivatives. A method for reducing the effective catalyst loading by "in situ recycling" is also presented.
- Gilmore, Nathan J.,Jones, Simon,Muldowney, Mark P.
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p. 2805 - 2808
(2007/10/03)
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- PRODUCTION OF OXY-MICHAEL ADDUCTS
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The invention provides a method of producing an oxy-Michael adduct comprising allowing a Michael acceptor to react with an alkoxide of an alcohol of formula R0H having a chiral centre at the hydroxy carbon, in the presence of a multidentate ligand. The
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- Enantioselective synthesis of cyanohydrin O-phosphates mediated by the bifunctional catalyst binolam-AlCl
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(R)- and (S)-binolam-AICI complexes act as bifunctional catalysts to mediate the enantioselective cyanophosphorylation of aldehydes at room temperature. The resulting chiral cyanohydrin O-phosphates can be reduced to β-aminoalcohols or, when suitably substituted, can be transformed into γ-cyanoallylic alcohols through palladium-catalyzed allylic substitution, without loss of enantiomeric excess (see scheme).
- Baeza, Alejandro,Casas, Jesus,Najera, Carmen,Sansano, Jose M.,Saa, Jose M.
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p. 3143 - 3146
(2007/10/03)
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- Highly diastereoselective oxy-Michael additions of enantiopure δ-lactol anions to nitroalkenes: Asymmetric synthesis of 1,2-amino alcohols
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The "naked" alkoxide 1 of (S)-6-methyl-δ-lactol acts as an excellent chiral hydroxide equivalent in highly diastereoselective oxy-Michael additions to nitroalkenes (see scheme). The excellent stereoinduction arises from what becomes a superb protecting gr
- Adderley, Nicola J.,Buchanan, David J.,Dixon, Darren J.,Laine, Dramane I.
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p. 4241 - 4244
(2007/10/03)
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- On the chemoselectivity and mechanism of desilylation of tert- butyldimethylsilyl ethers with TMSOTf
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A modified literature procedure is presented for desilylating primary and secondary tert-butyldimethylsilyl ethers involving TMSOTf followed by breakdown of the bis-silyloxonium ion in methanol. The chemoselectivity of the process with respect to TBDPS, T
- Hunter, Roger,Hinz, Wolfgang,Richards, Philip
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p. 3643 - 3646
(2007/10/03)
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- Asymmetric Synthesis via Acetal Templates. 5. Reactions with Cyanotrimethylsilane. Enantioselective Preparation of Cyanohydrins and Derivatives
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The titanium tetrachloride catalyzed reaction of the 2(R),4-(R)pentanediol acetals 1a-c with cyanotrimethylsilane proceeds in excellent yield and high diastereoselectivity to give cyanohydrin ethers 3a-c, and conditions have been developed for conversion of these ethers into cyanohydrins, β-amino alcohols and α-hydroxy esters with optical purities of greater then 90 percent.
- Elliott, John D.,Choi, Vanessa M. F.,Johnson, William S.
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p. 2294 - 2295
(2007/10/02)
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