Ruthenium-Catalyzed Redox-Neutral [4 + 1] Annulation of Benzamides and Propargyl Alcohols via C–H Bond ActivationInternal alkynes have been used widely in transition-metal-catalyzed cycloaddition reactions, in which they generally serve as two-carbon reaction partners. Herein, we report ruthenium(II)-catalyzed redox-neutral [4 + 1] annulation of benzamides and propargyl alcohols, in which propargyl alcohols act as one-carbon units. This synthetic utility of propargyl alcohols led to a series of potentially bioactive N-substituted quaternary isoindolinones with moderate to high yields under mild conditions. Without the requirement for an external metal oxidant, this title transformation is compatible with various functional groups, which further underscores its synthetic utility and versatile applicability. In addition, preliminary mechanism experiments have been conducted and a plausible mechanism is proposed.
Chemical Kinetic Resolution of Unprotected β‐Substituted β‐Amino Acids Using Recyclable Chiral LigandsShengbin Zhou, Jiang Wang, Xia Chen et al.|Angewandte Chemie International Edition|2014 The first chemical method for resolution of N,C-unprotected β-amino acids was developed through enantioselective formation and disassembly of nickel(II) complexes under operationally convenient conditions. The specially designed chiral ligands are inexpensive and can be quantitatively recycled along with isolation of the target β-substituted-β-amino acids in good yields and excellent enantioselectivity. The method features a broad synthetic generality including β-aryl, β-heteroaryl, and β-alkyl-derived β-amino acids. The procedure is easily scaled up, and was used for the synthetically and economically advanced preparation of the anti-diabetic drug sitagliptin.
Recyclable Ligands for the Non‐Enzymatic Dynamic Kinetic Resolution of Challenging α‐Amino AcidsYong Nian, Jiang Wang, Shengbin Zhou et al.|Angewandte Chemie International Edition|2015 Abstract Structurally simple and inexpensive chiral tridentate ligands were employed for substantially advancing the purely chemical dynamic kinetic resolution (DKR) of unprotected racemic tailor‐made α‐amino acids (TM‐α‐AAs), enabling the first DKR of TM‐α‐AAs bearing tertiary alkyl chains as well as multiple unprotected functional groups. Owing to the operationally convenient conditions, virtually complete stereoselectivity, and full recyclability of the source of chirality, this method should find wide applications for the preparation of TM‐α‐AAs, especially on large scale.
Asymmetric total synthesis and identification of tetrahydroprotoberberine derivatives as new antipsychotic agents possessing a dopamine D1, D2 and serotonin 5-HT1A multi-action profileHaifeng Sun, Liyuan Zhu, Huicui Yang et al.|Bioorganic & Medicinal Chemistry|2012 Asymmetric Synthesis of Sterically and Electronically Demanding Linear ω-Trifluoromethyl Containing Amino Acids via Alkylation of Chiral Equivalents of Nucleophilic Glycine and AlanineJiang Wang, Daizong Lin, Shengbin Zhou et al.|The Journal of Organic Chemistry|2010 An operationally convenient, scalable asymmetric synthesis of linear, ω-trifluoromethyl-containing amino acids, which were not previously produced in their enantiomerically pure form, has been developed via alkylation of chiral equivalents of nucleophilic glycine and alanine. The simplicity of the experimental procedures and high stereochemical outcome (yields up to 90% and diastereoselectivity up to 99%) of the presented method render these fluorinated amino acids readily available for systematic medicinal chemistry studies and de novo peptide design.