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Synthesis of β-alkynyl α-amino acids via palladium-catalyzed alkynylation of unactivated C(sp^3)-H bonds

Science China Chemistry 2015年第8期58卷 1345-1348页

作者： Bo Wang Gang He Gong Chen Department of Chemistry the Pennsylvania State University University Park

β-Di-substituted α-amino acids(AAs) contain adjacent carbon stereogenic centers and pose considerable synthetic challenge. Complementary to the conventional synthesis strategies based on the transformation of existing functional groups, we envisioned these molecules could be quickly accessed via selective functionalization of sp3 hybridized C-H bonds on the side chains of common α-AA precursors. We report a readily applicable method to prepare β-alkynyl α-amino acids via Pd-catalyzed diastereoselective C(sp3)-H alkynylation of common α-amino acids precursors with acetylene bromide.

关键词： α-amino acids C-H functionalization palladium

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Synergistic Catalysis with Azomethine Ylides

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Chinese Journal of Chemistry 2021年第1期39卷 15-24页

作者： Liang Wei Chun-Jiang Wang Engineering Research Center of Organosilicon Compounds&Materials Ministry of EducationCollege of Chemistry ond Molecular SciencesWuhan UniversityWuhanHubei 430072China State Key Laboratory of Elemento organic Chemistry Nankoi UniversityTionjin 300071China

Azomethine ylides are useful intermediates for the rapid construction of chiral N-containing ***,its synthetic potential has not been fully developed due to the limited reaction *** combination with synergistic catalysis and azomethine ylide chemistry,we have developed several types of novel catalytic system including Cu/Pd,Cu/Ir and PTC/Ir catalysis;which can convert readily-available azomethine ylides to various high-valued molecules such as unnatural a-amino acids,homoallylic amines and *** with the traditional mono-catalysis,the synergistic catalyst system exhibits enhanced catalytic efficiency and chiral induction ability in many *** addition,we have demonstrated that these strategies could be applied in the construction of bioactive compounds and natural products.

关键词： Azomethine ylides Synergistic catalysis Asymmetric synthesis N-Heterocycles α-amino acids

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Copper(I)/Sa BOX catalyzed highly diastereo- and enantio-selective cyclopropanation of cis-1,2-disubstituted olefins with a-nitrodiazoacetates

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Science Bulletin 2015年第2期60卷 210-215,I0002页

作者：冯良文王鹏王丽佳唐勇 The State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Collaborative Innovation Center of Chemical Science and Engineering

A copper-catalyzed highly stereoselective cyclopropanation of 1,2-disubstituted olefins with α-nitrodiazo acetates has been developed, giving the desired products in up to 97 % yields, up to 〉99/1 dr and up to 98 % ee, which provides an efficient access to the synthesis of optical active cyclopropane α-amino acids and unnatural α-amino acid derivatives.

关键词： Asymmetric catalysis Cyclopropanation Sidearm Bisoxazoline α-amino acids

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Temperature dependences and enthalpic discrimination of homochiral pairwise interactions of six α-amino acid enantiomers in pure water

Temperature dependences and enthalpic discrimination of homo...

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第十七届全国化学热力学和热分析学术会议

作者： Xingen Hu Liyuan Zhu Huaqin Wang Nan Chen College of Chemistry and Materials Engineering Wenzhou University

Dilution enthalpies of six enantiomers of α-amino acids（L-alanine vs. D-alanine, L-serine vs. D-serine, and L-proline vs. D-serine） in pure water were determined respectively at different temperatures（T = 288.15 to 323.15 K） by isothermal titration calorimetry（ITC）. Homochiral enthalpic pairwise interaction coefficients（hxx） of them at each temperature were evaluated from dilution enthalpies determined according to the Mc Millan-Mayer theory. The hxx values of α-alanine and α-proline enantiomers are all positive（hLL ＞ hDD ＞ 0）, signifying enthalpically repulsive effects, while those of α-serine enantiomers are all negative（hLL ＜ hDD ＜0）, signifying enthalpically attractive effects. However, for both of the cases, the hxx values increase uniformly and gradually with the elevating temperatures. The results indicate that there exists a slight but significant enthalpic discrimination effect in the homochiral pairwise interactions of these α-amino acid enantiomers, and that the increase of temperature promotes the predominance of hydrophobic interactions in the solutions, characterized by the positive growth of hxx values.

关键词： dilution enthalpy homochiral enthalpic pairwise interaction temperature dependence α-amino acids

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