The Experts below are selected from a list of 14508 Experts worldwide ranked by ideXlab platform
Masakatsu Shibasaki - One of the best experts on this subject based on the ideXlab platform.
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a direct catalytic asymmetric Aldol Reaction of α sulfanyl lactones efficient synthesis of spt inhibitors
ChemInform, 2012Co-Authors: Sho Takechi, Naoya Kumagai, Shigeo Yasuda, Masakatsu ShibasakiAbstract:The scalable and not moisture sensitive [indicated by the Reaction with the compound (IId)] title Aldol Reaction is developed.
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concise enantioselective synthesis of duloxetine via direct catalytic asymmetric Aldol Reaction of thioamide
Journal of Organic Chemistry, 2012Co-Authors: Yuta Suzuki, Ryo Yazaki, Naoya Kumagai, Mitsutaka Iwata, Masakatsu ShibasakiAbstract:Direct catalytic asymmetric Aldol Reaction of thioamide offers a new entry to the concise enantioselective synthesis of duloxetine. The direct Aldol protocol was scalable (>20 g) to afford the aldo...
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direct catalytic enantio and diastereoselective Aldol Reaction of thioamides
ChemInform, 2011Co-Authors: Mitsutaka Iwata, Naoya Kumagai, Ryo Yazaki, Ihon Chen, Devarajulu Sureshkumar, Masakatsu ShibasakiAbstract:A soft Lewis acid/hard Broensted base cooperative binary catalyst is effective for the exclusive generation of enolates from thioacetamides for the direct Aldol Reaction with α-nonbranched aliphatic aldehydes.
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direct catalytic enantio and diastereoselective Aldol Reaction of thioamides
Journal of the American Chemical Society, 2011Co-Authors: Mitsutaka Iwata, Naoya Kumagai, Ryo Yazaki, Ihon Chen, Devarajulu Sureshkumar, Masakatsu ShibasakiAbstract:A direct catalytic asymmetric Aldol Reaction of thioamides using a soft Lewis acid/hard Bronsted base cooperative catalyst comprising (R,R)-Ph-BPE/[Cu(CH3CN)4]PF6/LiOAr is described. Exclusive enolate generation from thioacetamides through a soft−soft interaction with the soft Lewis acid allowed for a direct Aldol Reaction to α-nonbranched aliphatic aldehydes, which are usually susceptible to self-condensation under conventional basic conditions. A hard Lewis basic phosphine oxide has emerged as an effective additive to constitute a highly active ternary soft Lewis acid/hard Bronsted base/hard Lewis base cooperative catalyst, enabling a direct enantio- and diastereoselective Aldol Reaction of thiopropionamides. Strict control of the amount of the hard Lewis base was essential to drive the catalytic cycle efficiently with a minimized retro-Aldol pathway, affording syn-Aldol products with high stereoselectivity. Divergent transformation of the thioamide functionality is an obvious merit of the present Aldol...
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catalytic asymmetric synthesis of α alkylidene β hydroxy esters via dynamic kinetic asymmetric transformation involving ba catalyzed direct Aldol Reaction
ChemInform, 2010Co-Authors: Akitake Yamaguchi, Shigeki Matsunaga, Masakatsu ShibasakiAbstract:A Ba-catalyzed dynamic kinetic asymmetric transformation (DYKAT) involving a direct Aldol/retro-Aldol Reaction of β,γ-unsaturated ester donors is described. A Ba(O-iPr)2/BINOL complex promoted the direct Aldol Reaction/isomerization sequence, and α-alkylidene-β-hydroxy esters were obtained from aryl, heteroaryl, alkenyl, and alkyl aldehydes under simple proton-transfer conditions with 99−87% ee and >20:1 to 15:1 α/γ selectivity.
Liu-zhu Gong - One of the best experts on this subject based on the ideXlab platform.
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Enantioselective relay catalytic cascade intramolecular hydrosiloxylation and mukaiyama Aldol Reaction
Chemistry - A European Journal, 2013Co-Authors: Pu-sheng Wang, Kang Nan Li, Xiao Le Zhou, Zhi Yong Han, Xiang Wu, Rui Guo, Liu-zhu GongAbstract:Cascading chemistry! The first practical relay catalytic cascade intramolecular hydrosiloxylation of arylacetylene and asymmetric Mukaiyama Aldol Reaction has been established to give synthetically useful products in high yields and with excellent ee (see scheme).
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enantioselective desymmetrization of prochiral cyclohexanone derivatives via the organocatalytic direct Aldol Reaction
Chemical Communications, 2007Co-Authors: Jun Jiang, Liu-zhu Gong, Shiwei Luo, Linfeng CunAbstract:Asymmetric desymmetrization of 4-substituted cyclohexanones using proline amide-catalyzed direct Aldol Reaction afforded β-hydroxyketones with three stereogenic centers in high enantioselectivities of up to >99% ee.
Seijiro Hosokawa - One of the best experts on this subject based on the ideXlab platform.
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syn selective kobayashi Aldol Reaction using acetals
Organic Letters, 2013Co-Authors: Hiroyuki Tsukada, Yuki Mukaeda, Seijiro HosokawaAbstract:The Kobayashi Aldol Reaction has been used to construct anti-Aldol products by remote stereoinduction. Since the product of the Kobayashi Aldol Reaction has a typical polyketide structure, this Reaction has been applied to the total synthesis of natural products. By varying this Reaction, it was found that the Reaction with acetals in the presence of Lewis acid proceeded to give syn adducts in high stereoselectivity. This is the first example of the stereoselective Reaction of the chiral dienol ether and acetals.
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syn selective kobayashi Aldol Reaction using the e e vinylketene silyl n o acetal
Organic Letters, 2012Co-Authors: Yuki Mukaeda, Takuya Kato, Seijiro HosokawaAbstract:The Kobayashi Aldol Reaction is one of the most powerful methods to synthesize the polyketide skeleton and has been applied to the total synthesis of natural products. This methodology has been used to construct anti-Aldol products, and only a few precedents on the syn-selective Kobayashi Aldol Reaction are known. A syn-selective Kobayashi Aldol Reaction by using the E,E-vinylketene silyl N,O-acetal and an excess amount of Lewis acid is presented.
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total synthesis of khafrefungin using highly stereoselective vinylogous mukaiyama Aldol Reaction
ChemInform, 2007Co-Authors: Shinichi Shirokawa, Seijiro Hosokawa, Atsuo Nakazaki, Mariko Shinoyama, Isao Ooi, Susumu KobayashiAbstract:A convergent total synthesis of khafrefungin was accomplished on the basis of (1) the highly stereoselective TiCl4-mediated vinylogous Mukaiyama Aldol Reaction using vinylketene silyl N,O-acetal and (2) syn-selective Aldol Reaction of enal 5a and ethyl ketone 6 followed by anti-dehydration under Mitsunobu conditions.
Makoto Nakajima - One of the best experts on this subject based on the ideXlab platform.
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enantioselective reductive Aldol Reaction using tertiary amine as hydride donor
ChemInform, 2012Co-Authors: Kazuki Osakama, Makoto Nakajima, Masaharu Sugiura, Shunsuke KotaniAbstract:A novel type of enantioselective Aldol Reaction between α,β-unsaturated ketones and aldehydes includes a sequence of conjugated reductions under conditions A).
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enantioselective reductive Aldol Reaction using tertiary amine as hydride donor
Tetrahedron Letters, 2012Co-Authors: Kazuki Osakama, Makoto Nakajima, Masaharu Sugiura, Shunsuke KotaniAbstract:Abstract An efficient method was developed for the enantioselective reductive Aldol Reaction of α,β-unsaturated ketones with aldehydes in the presence of a Lewis base catalyst; conjugate reduction using a tertiary amine and trichlorosilyl triflate, followed by an Aldol Reaction with BINAP dioxide (BINAPO) as an organocatalyst, gave the corresponding product in high yield with high stereoselectivity.
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trichlorosilyl triflate mediated enantioselective directed cross Aldol Reaction between ketones using a chiral phosphine oxide as an organocatalyst
Chemical Communications, 2012Co-Authors: Shohei Aoki, Shunsuke Kotani, Masaharu Sugiura, Makoto NakajimaAbstract:Trichlorosilyl triflate-promoted directed cross-Aldol Reaction between ketones in the presence of a chiral phosphine oxide as an organocatalyst is described. This is the first enantioselective cross-Aldol Reaction between simple ketones with good enantioselectivity.
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trichlorosilyl triflate for enantioselective direct type Aldol Reaction with chiral phosphine oxide
Tetrahedron Letters, 2011Co-Authors: Shunsuke Kotani, Masaharu Sugiura, Shohei Aoki, Makoto NakajimaAbstract:Trichlorosilyl triflate, in the presence of a chiral Lewis base catalyst, provides an effective method for the enantioselective direct-type Aldol Reaction of aldehydes and ketones. A chiral Lewis base induces both the production and activation of trichlorosilyl enol ether, yielding an Aldol product in good yield and with high diastereo- and enantioselectivities.
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enantioselective Aldol Reaction of trimethoxysilyl enol ether catalyzed by lithium binaphtholate
Organic Letters, 2004Co-Authors: Makoto Nakajima, Tadao Ishizuka, Yuya Orito, Shunichi HashimotoAbstract:An Aldol Reaction of trimethoxysilyl enol ether catalyzed by lithium binaphtholate, in which water serves as an additive and plays a pivotal role in stereoselectivities, was developed. This is the first example of an Aldol Reaction of trimethoxysilyl enol ether catalyzed by a chiral base.
Jacek Mlynarski - One of the best experts on this subject based on the ideXlab platform.
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tertiary amine promoted asymmetric Aldol Reaction of aldehydes
ChemInform, 2015Co-Authors: Bartosz Gut, Jacek MlynarskiAbstract:The first direct enantioselective organocatalytic self-Aldol Reaction of α-oxyaldehydes is developed.
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general switch in regioselectivity in the mukaiyama Aldol Reaction of silyloxyfuran with aldehydes in aqueous solvents
Chemical Communications, 2012Co-Authors: Marta Woyciechowska, Jacek Mlynarski, Gwenael Forcher, Szymon BudaAbstract:An unexpected yet disciplined course of catalytic Mukaiyama-Aldol Reaction instead of the expected vinylogous Mukaiyama-Aldol Reaction has been observed for the Reaction of silyloxyfuran with various aldehydes under Lewis acid catalytic control in water-containing solvents.
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direct asymmetric Aldol Reaction of hydroxyacetone promoted by chiral tertiary amines
ChemInform, 2009Co-Authors: Joanna Paradowska, Maria Rogozinska, Jacek MlynarskiAbstract:Abstract The tertiary amine-catalyzed direct asymmetric Aldol Reaction of hydroxyacetone with a variety of aromatic aldehydes is developed. Using 5–10 mol % of quinidine as catalyst, the direct Aldol condensation products were obtained in reasonable yields and with asymmetric induction (up to 47% ee). The present approach is extended to asymmetric organocatalytic strategies for the preparation of 1,2-diols.