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Publication
Featured researches published by Tatsunori Sato.
Amino Acids | 2013
Alexander E. Sorochinsky; José Luis Aceña; Hiroki Moriwaki; Tatsunori Sato; Vadim A. Soloshonok
Alkylations of chiral or achiral Ni(II) complexes of glycine Schiff bases constitute a landmark in the development of practical methodology for asymmetric synthesis of α-amino acids. Straightforward, easy preparation as well as high reactivity of these Ni(II) complexes render them ready available and inexpensive glycine equivalents for preparing a wide variety of α-amino acids, in particular on a relatively large scale. In the case of Ni(II) complexes containing benzylproline moiety as a chiral auxiliary, their alkylation proceeds with high thermodynamically controlled diastereoselectivity. Similar type of Ni(II) complexes derived from alanine can also be used for alkylation providing convenient access to quaternary, α,α-disubstituted α-amino acids. Achiral type of Ni(II) complexes can be prepared from picolinic acid or via recently developed modular approach using simple secondary or primary amines. These Ni(II) complexes can be easily mono/bis-alkylated under homogeneous or phase-transfer catalysis conditions. Origin of diastereo-/enantioselectivity in the alkylations reactions, aspects of practicality, generality and limitations of this methodology is critically discussed.
Amino Acids | 2013
Alexander E. Sorochinsky; José Luis Aceña; Hiroki Moriwaki; Tatsunori Sato; Vadim A. Soloshonok
Abstract This review provides a comprehensive treatment of literature data dealing with asymmetric synthesis of α-amino-β-hydroxy and α,β-diamino acids via homologation of chiral Ni(II) complexes of glycine Schiff bases using aldol and Mannich-type reactions. These reactions proceed with synthetically useful chemical yields and thermodynamically controlled stereoselectivity and allow direct introduction of two stereogenic centers in a single operation with predictable stereochemical outcome. Furthermore, new application of Ni(II) complexes of α-amino acids Schiff bases for deracemization of racemic α-amino acids and (S) to (R) interconversion providing additional synthetic opportunities for preparation of enantiomerically pure α-amino acids, is also reviewed. Origin of observed diastereo-/enantioselectivity in the aldol, Mannich-type and deracemization reactions, generality and limitations of these methodologies are critically discussed.
Angewandte Chemie | 2014
Ryosuke Takeda; Akie Kawamura; Aki Kawashima; Tatsunori Sato; Hiroki Moriwaki; Kunisuke Izawa; Kenichi Akaji; Shuni Wang; Hong Liu; José Luis Aceña; Vadim A. Soloshonok
Reported herein is the first purely chemical method for the dynamic kinetic resolution (DKR) of unprotected racemic α-amino acids (α-AAs), a method which can rival the economic efficiency of the enzymatic reactions. The DKR reaction principle can be readily applied for S/R interconversions of α-AAs, the methodological versatility of which is unmatched by biocatalytic approaches. The presented process features a virtually complete stereochemical outcome, fully recyclable source of chirality, and operationally simple and convenient reaction conditions, thus allowing its ready scalability. A quite unique and novel mode of the thermodynamic control over the stereochemical outcome, including an exciting interplay between axial, helical, and central elements of chirality is proposed.
Amino Acids | 2016
Aki Kawashima; Shuangjie Shu; Ryosuke Takeda; Akie Kawamura; Tatsunori Sato; Hiroki Moriwaki; Jiang Wang; Kunisuke Izawa; José Luis Aceña; Vadim A. Soloshonok; Hong Liu
Asymmetric synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid (vinyl-ACCA) is in extremely high demand due to the pharmaceutical importance of this tailor-made, sterically constrained α-amino acid. Here we report the development of an advanced procedure for preparation of the target amino acid via two-step SN2 and SN2′ alkylation of novel axially chiral nucleophilic glycine equivalent. Excellent yields and diastereoselectivity coupled with reliable and easy scalability render this method of immediate use for practical synthesis of (1R,2S)-vinyl-ACCA.
RSC Advances | 2015
Aki Kawashima; Chen Xie; Haibo Mei; Ryosuke Takeda; Akie Kawamura; Tatsunori Sato; Hiroki Moriwaki; Kunisuke Izawa; Jianlin Han; José Luis Aceña; Vadim A. Soloshonok
This work describes a new process for the asymmetric synthesis of (1R,2S)-1-amino-2-vinylcyclopropanecarboxylic acid of high pharmaceutical importance. The sequence of the reactions includes PTC alkylation (SN2), homogeneous SN2′ cyclization followed by disassembly of the resultant Ni(II) complex. All reactions are conducted under operationally convenient conditions and suitably scaled up to 6 g of the starting Ni(II) complex.
Current Pharmaceutical Design | 2017
Shuni Wang; Yibing Wang; Jiang Wang; Tatsunori Sato; Kunisuke Izawa; Vadim A. Soloshonok; Hong Liu
Hepatitis C is a current pandemic liver disease caused by the hepatitis C virus (HCV) with high morbidity and mortality. Recently, the direct-acting antiviral agents (DAAs) targeting HCV NS3/4A, NS5A and NS5B have become the most effective therapies against HCV infection in the clinical treatment. Among them, the second-generation of NS3/4A inhibitors have emerged as the mainstay of the DAA therapies, which are derived from the peptide substrate of NS3/4A protease and modified with various tailor-made amino acids in order to achieve high sustained virologic response (SVR) against HCV. This review summarizes sixteen examples of the second-generation of HCV NS3/4A inhibitors, mainly focusing on the clinical application, structure development, structure-activity relationship (SAR) and their synthesis.
ACS Omega | 2018
Ryosuke Takeda; Aki Kawashima; Junya Yamamoto; Tatsunori Sato; Hiroki Moriwaki; Kunisuke Izawa; Hidenori Abe; Vadim A. Soloshonok
In this work, we disclose an advanced general process for the synthesis of tailor-made α-amino acids (α-AAs) via tandem alkylation–second-order asymmetric transformation. The first step is the alkylation of the chiral Ni(II) complex of glycine Schiff base, which is conducted under mild phase-transfer conditions allowing the structural construction of target α-AAs. The second step is based on the methodologically rare second-order asymmetric transformation, resulting in nearly complete precipitation of the corresponding (SC,RN,RC)-configured diastereomer, which can be collected by a simple filtration. The operational convenience and potential scalability of all experimental procedures, coupled with excellent stereochemical outcome, render this method of high synthetic value for the preparation of various tailor-made α-AAs.
Journal of Fluorine Chemistry | 2013
José Luis Aceña; Alexander E. Sorochinsky; Hiroki Moriwaki; Tatsunori Sato; Vadim A. Soloshonok
Journal of Fluorine Chemistry | 2013
Alexander E. Sorochinsky; Hisanori Ueki; José Luis Aceña; Trevor K. Ellis; Hiroki Moriwaki; Tatsunori Sato; Vadim A. Soloshonok
Organic and Biomolecular Chemistry | 2013
Alexander E. Sorochinsky; Hisanori Ueki; José Luis Aceña; Trevor K. Ellis; Hiroki Moriwaki; Tatsunori Sato; Vadim A. Soloshonok