- A "traceless" Directing Group Enables Catalytic SN2 Glycosylation toward 1,2- cis-Glycopyranosides
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Generally applicable and stereoselective formation of 1,2-cis-glycopyranosidic linkage remains a long sought after yet unmet goal in carbohydrate chemistry. This work advances a strategy to this challenge via stereoinversion at the anomeric position of 1,2-trans glycosyl ester donors. This SN2 glycosylation is enabled under gold catalysis by an oxazole-based directing group optimally tethered to a leaving group and achieved under mild catalytic conditions, in mostly excellent yields, and with good to outstanding selectivities. The strategy is also applied to the synthesis of oligosaccharides.
- Fu, Yue,Liu, Peng,Ma, Xu,Zhang, Liming,Zheng, Zhitong,Zhu, Xijun
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supporting information
p. 11908 - 11913
(2021/08/20)
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- Inhibitory effects of N-(acryloyl)benzamide derivatives on tyrosinase and melanogenesis
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Targeting of tyrosinase has proven to be the best means of identifying safe, efficacious, and potent tyrosinase inhibitors for whitening skin. We designed and synthesized ten NAB (N-(acryloyl)benzamide) derivatives (1a–1j) using the Horner-Wadsworth-Emmon
- Lee, Sanggwon,Ullah, Sultan,Park, Chaeun,Won Lee, Hee,Kang, Dongwan,Yang, Jungho,Akter,Park,Chun, Pusoon,Moon, Hyung Ryong
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p. 3929 - 3937
(2019/07/30)
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- Derivatives and application to the asymmetric synthesis of unnatural α-amino acid derivative
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We describe herein a manganese(IV) oxide-mediated oxidation of N-p-methoxyphenyl (PMP)-protected glycine derivatives for the synthesis of a-imino carboxylic acid derivatives. Using this methodology, utilization of unstable glyoxic acid derivatives was avoided. Furthermore, using this methodology we synthesized novel a-imino carboxylic acid derivatives such as a-imino phenyl ester, perfluoroalkyl etsers, imides, and thioester. The asymmetric Mannich reaction of those novel imine derivatives with 1,3-dicarbonyl compound is also described, and the novel a-imino imide gave improved chemical yield and stereoselectivity compared with those obtained by the use of the conventional a-imino ester-type substrate.
- Inokuma, Tsubasa,Jichu, Takahisa,Nishida, Kodai,Shigenaga, Akira,Otaka, Akira
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p. 573 - 581
(2017/06/07)
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- A convenient method for preparation of α-imino carboxylic acid derivatives and application to the asymmetric synthesis of unnatural α-amino acid derivative
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We describe herein a manganese(IV) oxide-mediated oxidation of N-p-methoxyphenyl (PMP)-protected glycine derivatives for the synthesis of α-imino carboxylic acid derivatives. Using this methodology, utilization of unstable glyoxic acid derivatives was avo
- Inokuma, Tsubasa,Jichu, Takahisa,Nishida, Kodai,Shigenaga, Akira,Otaka, Akira
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p. 573 - 581
(2019/12/26)
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- Catalytic Asymmetric Total Syntheses of Quinine and Quinidine
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The catalytic, asymmetric syntheses of quinine and quinidine were achieved in 16 steps. The recently developed salen(Al)-catalyzed enantioselective Michael addition of methyl cyanoacetate served to set the crucial C4 stereocenter in 92% ee, and a late-stage asymmetric dihydroxylation was used to differentiate the common intermediate and access the two desired diastereomeric products with high selectivity. Copyright
- Raheem, Izzat T.,Goodman, Steven N.,Jacobsen, Eric N.
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p. 706 - 707
(2007/10/03)
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- A Practical Synthesis of α,β-Unsaturated Imides, Useful Substrates for Asymmetric Conjugate Addition Reactions
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We report an improved synthesis of α,β-unsaturated imides, a class of compounds that has been identified as broadly useful in (salen)aluminum-catalyzed asymmetric conjugate addition reactions. An efficient, scaleable procedure for the synthesis of phospho
- Goodman, Steven N.,Jacobsen, Eric N.
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p. 953 - 956
(2007/10/03)
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