1
|
Odanaka Y, Kanemitsu T, Iwasaki K, Mochizuki Y, Miyazaki M, Nagata K, Kato M, Itoh T. Asymmetric Michael addition of malonic diesters to acrylates by phase-transfer catalysis toward the construction of quaternary stereogenic α-carbons. Tetrahedron 2019. [DOI: 10.1016/j.tet.2018.11.037] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
2
|
Liniger M, Liu Y, Stoltz BM. Sequential Ruthenium Catalysis for Olefin Isomerization and Oxidation: Application to the Synthesis of Unusual Amino Acids. J Am Chem Soc 2017; 139:13944-13949. [PMID: 28918631 PMCID: PMC5628162 DOI: 10.1021/jacs.7b08496] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
How can you use a ruthenium isomerization catalyst twice? A ruthenium-catalyzed sequence for the formal two-carbon scission of allyl groups to carboxylic acids has been developed. The reaction includes an initial isomerization step using commercially available ruthenium catalysts followed by in situ transformation of the complex to a metal-oxo species, which is capable of catalyzing subsequent oxidation reactions. The method enables enantioselective syntheses of challenging α-tri- and tetrasubstituted α-amino acids including an expedient total synthesis of the antiepileptic drug levetiracetam.
Collapse
Affiliation(s)
| | - Yiyang Liu
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| | - Brian M. Stoltz
- Warren and Katherine Schlinger Laboratory for Chemistry and Chemical Engineering, Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125, United States
| |
Collapse
|
3
|
Badiola E, Fiser B, Gómez-Bengoa E, Mielgo A, Olaizola I, Urruzuno I, García JM, Odriozola JM, Razkin J, Oiarbide M, Palomo C. Enantioselective Construction of Tetrasubstituted Stereogenic Carbons through Brønsted Base Catalyzed Michael Reactions: α′-Hydroxy Enones as Key Enoate Equivalent. J Am Chem Soc 2014; 136:17869-81. [DOI: 10.1021/ja510603w] [Citation(s) in RCA: 106] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Eider Badiola
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Béla Fiser
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Enrique Gómez-Bengoa
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Antonia Mielgo
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Iurre Olaizola
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Iñaki Urruzuno
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Jesús M. García
- Departamento
de Química Aplicada, Institute of Advanced Materials (INAMAT), Universidad Pública de Navarra, 31006-Pamplona, Spain
| | - José M. Odriozola
- Departamento
de Química Aplicada, Institute of Advanced Materials (INAMAT), Universidad Pública de Navarra, 31006-Pamplona, Spain
| | - Jesús Razkin
- Departamento
de Química Aplicada, Institute of Advanced Materials (INAMAT), Universidad Pública de Navarra, 31006-Pamplona, Spain
| | - Mikel Oiarbide
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| | - Claudio Palomo
- Departamento
de Química Orgánica I, Universidad del País Vasco, Manuel Lardizábal 3, 20018-San Sebastián, Spain
| |
Collapse
|
4
|
Synthesis of β-disubstituted β-amino isoxazolyl ketones by addition of ketimines with isoxazolyl methyl ketone enolates. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.02.053] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
5
|
Tomasevich LL, Collum DB. Structure determination using the method of continuous variation: lithium phenolates solvated by protic and dipolar aprotic ligands. J Org Chem 2013; 78:7498-507. [PMID: 23806055 PMCID: PMC3759316 DOI: 10.1021/jo401080n] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The method of continuous variation (MCV) was used in conjunction with (6)Li NMR spectroscopy to characterize four lithium phenolates solvated by a range of solvents, including N,N,N',N'-tetramethylethylenediamine, Et2O, pyridine, protic amines, alcohols, and highly dipolar aprotic solvents. Dimers, trimers, and tetramers were observed, depending on the precise lithium phenolate-solvent combinations. Competition experiments (solvent swaps) provide insights into the relative propensities toward mixed solvation.
Collapse
Affiliation(s)
- Laura L. Tomasevich
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| | - David B. Collum
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301
| |
Collapse
|
6
|
Lazny R, Wolosewicz K. An expedient preparation of amine-free lithium enolates using immobilized amide reagents. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2012.12.067] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
7
|
Liu Z, Mehta SJ, Lee KS, Grossman B, Qu H, Gu X, Nichol GS, Hruby VJ. Thio-Claisen Rearrangement Used in Preparing Anti-β-Functionalized γ,δ-Unsaturated Amino Acids: Scope and Limitations. J Org Chem 2012; 77:1289-300. [DOI: 10.1021/jo201753q] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Zhihua Liu
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Sukeshi J. Mehta
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Kwang-Soo Lee
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Bryan Grossman
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Hongchang Qu
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Xuyuan Gu
- Small Molecule Pharmaceuticals, Nektar Therapeutics, 490 Discovery Drive, Huntsville,
Alabama 35758, United States
| | - Gary S. Nichol
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| | - Victor J. Hruby
- Department of Chemistry and
Biochemistry, University of Arizona, 1306
East University Boulevard, Tucson, Arizona 85721, United States
| |
Collapse
|
8
|
BOLIN DAVIDR, SYTWU IOUIOU, HUMIEC FRANK, MEIENHOFER JOHANNES. Preparation of oligomer-free Nα-Fmoc and Nα-urethane amino acids. ACTA ACUST UNITED AC 2009. [DOI: 10.1111/j.1399-3011.1989.tb00694.x] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
9
|
Liu Z, Qu H, Gu X, Min BJ, Nyberg J, Hruby VJ. Enantioselective synthesis of anti-beta-substituted gamma,delta-unsaturated amino acids: a highly selective asymmetric thio-Claisen rearrangement. Org Lett 2008; 10:4105-8. [PMID: 18702500 PMCID: PMC2654228 DOI: 10.1021/ol801657q] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A novel synthesis of optically active anti-beta-substituted gamma,delta-unsaturated amino acids via a thio-Claisen rearrangement has been achieved. A 2,5-diphenylpyrrolidine was used as a C2-symmetric chiral auxiliary to control the stereochemistry, giving good yields and excellent diastereoselectivities and enantioselectivities.
Collapse
Affiliation(s)
- Zhihua Liu
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| | - Hongchang Qu
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| | - Xuyuan Gu
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| | - Byoung J. Min
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| | - Joel Nyberg
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| | - Victor J. Hruby
- Department of Chemistry, University of Arizona, Tucson, AZ 85721, U. S. A
| |
Collapse
|
10
|
Ma Y, Collum DB. Lithium diisopropylamide-mediated reactions of imines, unsaturated esters, epoxides, and aryl carbamates: influence of hexamethylphosphoramide and ethereal cosolvents on reaction mechanisms. J Am Chem Soc 2007; 129:14818-25. [PMID: 17985891 DOI: 10.1021/ja074554e] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Several reactions mediated by lithium diisopropylamide (LDA) with added hexamethylphosphoramide (HMPA) are described. The N-isopropylimine of cyclohexanone lithiates via an ensemble of monomer-based pathways. Conjugate addition of LDA/HMPA to an unsaturated ester proceeds via di- and tetra-HMPA-solvated dimers. Deprotonation of norbornene epoxide by LDA/HMPA proceeds via an intermediate metalated epoxide as a mixed dimer with LDA. Ortholithiation of an aryl carbamate proceeds via a mono-HMPA-solvated monomer-based pathway. Dependencies on THF and other ethereal cosolvents suggest that secondary-shell solvation effects are important in some instances. The origins of the inordinate mechanistic complexity are discussed.
Collapse
Affiliation(s)
- Yun Ma
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
| | | |
Collapse
|
11
|
Buron F, Deguest G, Bischoff L, Fruit C, Marsais F. On the racemisation of aspartic anhydride during its preparation. ACTA ACUST UNITED AC 2007. [DOI: 10.1016/j.tetasy.2007.07.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
12
|
Bezencon O, Seebach D. Alkylations of Chiral Imidazolidinones Derived from Di- and Triglycine and Attempts at Cyclisations to Give Cycloisodityrosines. European J Org Chem 2006. [DOI: 10.1002/jlac.199619960805] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
13
|
|
14
|
Synthesis of novel chiral hydrobenzoin mono-tert-butyl ethers derived from m-hydrobenzoin and their application as chiral auxiliaries in the diastereoselective reduction of α-keto esters. ACTA ACUST UNITED AC 2005. [DOI: 10.1016/j.tetasy.2005.06.033] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
15
|
Obrecht D, Spiegler C, Schönholzer P, Müller K, Heimgartner H, Stierli F. A New General Approach to Enantiomerically Pure Cyclic and Open-Chain (R)- and (S)-α,α-Disubstituted α-Amino Acids. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19920750522] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
16
|
Häner R, Olano B, Seebach D. Preparation and C-Alkylation of Enantiomerically PureS-Phenyl Aziridinecarbothioates. On the Structure of Small-Ring Ester Lithium Enolates. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19870700704] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
17
|
Laube T, Dunitz JD, Seebach D. Über die Wechselwirkung zwischen Lithium-enolaten und sekundären Aminen in Lösung und im Kristall. Helv Chim Acta 2004. [DOI: 10.1002/hlca.19850680530] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
18
|
Harding CI, Dixon DJ, Ley SV. The preparation and alkylation of a butanedione-derived chiral glycine equivalent and its use for the synthesis of α-amino acids and α,α-disubstituted amino acids. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.063] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
19
|
Seebach D, Kimmerlin T, Šebesta R, Campo MA, Beck AK. How we drifted into peptide chemistry and where we have arrived at. Tetrahedron 2004. [DOI: 10.1016/j.tet.2004.06.043] [Citation(s) in RCA: 104] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
20
|
Zhao P, Condo A, Keresztes I, Collum DB. Reaction of Ketones with Lithium Hexamethyldisilazide: Competitive Enolizations and 1,2-Additions. J Am Chem Soc 2004; 126:3113-8. [PMID: 15012141 DOI: 10.1021/ja030582v] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Reaction of 2-methylcyclohexanone with lithium hexamethyldisilazide (LiHMDS, TMS(2)NLi) displays highly solvent-dependent chemoselectivity. LiHMDS in THF/toluene effect enolization. Rate studies using in situ IR spectroscopy are consistent with a THF concentration-dependent monomer-based pathway. LiHMDS in pyrrolidine/toluene affords exclusively 1,2-addition of the pyrrolidine fragment to form an alpha-amino alkoxide-LiHMDS mixed dimer shown to be a pair of conformers by using (6)Li, (15)N, and (13)C NMR spectroscopies. Rate studies are consistent with a monomer-based transition structure [(TMS(2)NLi)(ketone)(pyrrolidine)(3)](). The partitioning between enolization and 1,2-addition is kinetically controlled.
Collapse
Affiliation(s)
- Pinjing Zhao
- Department of Chemistry and Chemical Biology, Baker Laboratory, Cornell University, Ithaca, New York 14853-1301, USA
| | | | | | | |
Collapse
|
21
|
Yee NK, Nummy LJ, Frutos RP, Song JJ, Napolitano E, Byrne DP, Jones PJ, Farina V. Practical synthesis of a cell adhesion inhibitor by self-regeneration of stereocenters. ACTA ACUST UNITED AC 2003. [DOI: 10.1016/j.tetasy.2003.08.039] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
22
|
Jung ME, Toyota A. Preparation of 4'-substituted thymidines by substitution of the thymidine 5'-esters. J Org Chem 2001; 66:2624-35. [PMID: 11304180 DOI: 10.1021/jo001223a] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
tert-Butyl thymidylate 3 was prepared from thymidine 1 in six steps and 67% overall yield. When the lithium trianion of 3 (prepared by treatment of 3 with excess LDA and then excess tert-butyllithum) is reacted with electrophiles, trapping occurs stereoselectively from either the alpha- or beta-face depending on the electrophile (Scheme 1). Deuterioacetic acid in deuteriomethanol affords mainly the alpha-deuterated product (4a/4b = 2.4:1) while all other electrophiles, e.g., phenylselenenyl chloride, allyl bromide, and N-fluorobenzenesulfonimide (NFSI), give predominately (or completely) the products of attack from the beta-face (5bcd/4bcd = 3.7:1 to 100:0). The structures of the products were determined by coupling constant analysis of both the initial compounds and the diols 6bcd prepared by ester reduction and by formation of the acetonides 7bc. The methyl ester of the 3'-epimer of thymidylic acid 9 was also prepared from thymidine 1 in nine steps and 74% overall yield. When the lithium trianion of 9 (prepared by treatment of 9 with excess LDA and then excess tert-butyllithum) is reacted with electrophiles, trapping also occurs stereoselectively with attack on either the alpha- or beta-face depending on the electrophile (Scheme 2). Again, deuterioacetic acid in deuteriomethanol affords mainly the beta-deuterated product (11a/10a = 1.6:1) while all other electrophiles, e.g., phenylselenenyl chloride, methyl iodide, allyl bromide, and NFSI, gave predominately (or completely) the product of attack from the alpha-face (8.7:1 to 100: 0). Again, the structures of the products were determined by coupling constant analysis of both the initial compounds, and the diols 12b-e were prepared by reduction of the ester and by formation of the acetonides 13bcd. A rationale has been developed using molecular mechanics calculations to explain the diastereoselectivity that involves staggered axial attack on the sp(2) carbon opposite to the pseudoaxial alkoxy group in the most stable half-chair conformation of the enolates, as shown in Schemes 3-5.
Collapse
Affiliation(s)
- M E Jung
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA.
| | | |
Collapse
|
23
|
Calmès M, Glot C, Martinez J. Investigation into the enantioselective protonation of enolate Schiff bases with (R)-pantolactone. ACTA ACUST UNITED AC 2001. [DOI: 10.1016/s0957-4166(00)00500-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
24
|
Yee NK. Self-regeneration of stereocenters: a practical enantiospecific synthesis of LFA-1 antagonist BIRT-377. Org Lett 2000; 2:2781-3. [PMID: 10964364 DOI: 10.1021/ol000147v] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] An efficient enantiospecific synthesis of the LFA-1 antagonist BIRT-377 has been achieved in 43% overall yield in eight steps. The key transformations involve the stereospecific formation of the trans imidazolidinone 7, subsequent alkylation, and the efficient hydrolysis of disubstituted imidazolidinone 9. The process is practical, robust, and cost-effective; it has been successfully implemented in the pilot plant to produce multikilogram quantities of the drug BIRT-377.
Collapse
Affiliation(s)
- N K Yee
- Department of Chemical Development, Boehringer Ingelheim Pharmaceuticals, Inc., 900 Old Ridgebury Road, P.O. Box 368, Ridgefield, Connecticut 06877-0368, USA.
| |
Collapse
|
25
|
Abele S, Seebach D. Preparation of Achiral and of Enantiopure Geminally Disubstituted β-Amino Acids for β-Peptide Synthesis. European J Org Chem 2000. [DOI: 10.1002/(sici)1099-0690(200001)2000:1<1::aid-ejoc1>3.0.co;2-6] [Citation(s) in RCA: 241] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
26
|
Trost BM, Ariza X. Enantioselective Allylations of Azlactones with Unsymmetrical Acyclic Allyl Esters. J Am Chem Soc 1999. [DOI: 10.1021/ja992754n] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Barry M. Trost
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080
| | - Xavier Ariza
- Contribution from the Department of Chemistry, Stanford University, Stanford, California 94305-5080
| |
Collapse
|
27
|
Abstract
Various methodologies published in the literature dealing with alpha-amino carboxylic acid asymmetric synthesis are presented in a digest form. In each case, only some recent or most typical works are mentioned.
Collapse
Affiliation(s)
- M Calmes
- Laboratoire des Aminoacides, Peptides et Protéines, UMR-CNRS 5810, Universités Montpellier I, France
| | | |
Collapse
|
28
|
|
29
|
Cativiela C, Díaz-de-Villegas MD, Gálvez J, Lapeña Y. On the synthesis of (S)-α-methylaspartic acid by diastereoselective alkylation of a chiral 2-cyanopropanoate. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00249-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
30
|
Kelly NM, Sutherland A, Willis CL. Syntheses of amino acids incorporating stable isotopes. Nat Prod Rep 1997. [DOI: 10.1039/np9971400205] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
31
|
Sawamura M, Nakayama Y, Tang WM, Ito Y. Enantioselective Allylation of Nitro Group-Stabilized Carbanions Catalyzed by Chiral Crown Ether Phosphine−Palladium Complexes. J Org Chem 1996. [DOI: 10.1021/jo961343b] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masaya Sawamura
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan, and Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Kyoto 606-01, Japan
| | - Yuki Nakayama
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan, and Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Kyoto 606-01, Japan
| | - Wen-Ming Tang
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan, and Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Kyoto 606-01, Japan
| | - Yoshihiko Ito
- Department of Chemistry, School of Science, The University of Tokyo, Hongo, Bunkyo-ku, Tokyo 113, Japan, and Department of Synthetic Chemistry and Biological Chemistry, Faculty of Engineering, Kyoto University, Kyoto 606-01, Japan
| |
Collapse
|
32
|
Seebach D, Sting AR, Hoffmann M. Die Selbstregeneration von Stereozentren (SRS) — Anwendungen, Grenzen und Preisgabe eines Syntheseprinzips. Angew Chem Int Ed Engl 1996. [DOI: 10.1002/ange.19961082304] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
33
|
Welch JT, Plummer JS, Herbert RW. The generation of the diisopropyl nitroxide radical during the reaction of lithium diisopropylamide with α-fluoroacetate esters. RESEARCH ON CHEMICAL INTERMEDIATES 1996. [DOI: 10.1163/156856796x00485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
|
34
|
López A, Moreno-Mañas M, Pleixats R, Roglans A, Ezquerra J, Pedregal C. Ethyl N-(diphenylmethylene)glycinate as anionic glycine equivalent. Monoalkylation, dialkylation and Michael additions under solid-liquid phase-transfer catalysis. Tetrahedron 1996. [DOI: 10.1016/0040-4020(96)00395-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
35
|
Elemes Y, Ragnarsson U. Synthesis of enantiopure α-deuteriated Boc-L-amino acids. ACTA ACUST UNITED AC 1996. [DOI: 10.1039/p19960000537] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
36
|
A novel synthesis of (R)- and (S)-α-alkylated aspartic and glutamic acids: α-alkylated aspartic succinimides as new type of β-turn type II and II′ mimetics. Tetrahedron 1995. [DOI: 10.1016/0040-4020(95)00665-u] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
37
|
Studer A, Hintermann T, Seebach D. Synthesis and First Applications of a New Chiral Auxiliary (tert-butyl 2-(tert-butyl)-5,5-dimethyl-4-oxoimidazolidine-1-carboxylate). Helv Chim Acta 1995. [DOI: 10.1002/hlca.19950780512] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
|
38
|
Studer A, Seebach D. Enantioselective synthesis of α-branched α-amino acids with bulky substituents. ACTA ACUST UNITED AC 1995. [DOI: 10.1002/jlac.199519950231] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
39
|
Alonso F, Davies SG. Enantiospecific conversion of (S)-alanine to (R)-α-methyl phenylalanine. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0957-4166(95)00011-d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
40
|
Asymmetric syntheses of α-amino acids. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/s1874-5148(06)80005-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/14/2023]
|
41
|
Resolution and regioselective protection of glutamic acid analogues. I- resolution of diastereomeric α-boroxazolidone derivatives. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0957-4166(94)80036-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
|
42
|
Lankiewicz L, Nyassé B, Fransson B, Grehn L, Ragnarsson U. Synthesis of amino acid derivatives substituted in the backbone with stable isotopes for application in peptide synthesis. ACTA ACUST UNITED AC 1994. [DOI: 10.1039/p19940002503] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
43
|
Enantiospecific synthesis of amino acids: preparation of (R)- and (S)-α-methylaspartic acid from (S)-tryptophan. Tetrahedron Lett 1992. [DOI: 10.1016/s0040-4039(00)92648-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
44
|
Belokon' YN, Tararov VI, Maleev VI, Motsishkite SM, Vitt SV, Chernoglazova NI, Savel'eva TF, Saporovskaya MB. Asymmetric synthesis of aspartic and ?-methylaspartic acids via Ni(II) complexes with schiff bases of glycine and alanine and chiral carbonyl-containing reagents. Russ Chem Bull 1991. [DOI: 10.1007/bf00961233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
45
|
Versatile Stereoselective Synthesis of Completely Protected Trifunctional ?-Methylated ?-Amino Acids Starting from Alanine. Helv Chim Acta 1991. [DOI: 10.1002/hlca.19910740414] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
46
|
Belokon' YN, Tararov VI, Savel'eva TF. Preparative asymmetric synthesis of (R)- and (S)-?-methylserine Ni(II) complex with a Schiff base of ?-alanine and (S)-2-[(N-benzylprolyl)amino]benzophenone. ACTA ACUST UNITED AC 1991. [DOI: 10.1007/bf00961373] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
|
47
|
Dolder XSM, Tamm C. Synthetic studies directed toward the pseurotins. Part II. Synthesis of related highly functionalized furan-3(2H)-ones. Helv Chim Acta 1990. [DOI: 10.1002/hlca.19900730229] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
48
|
Ackermann J, Matthes M, Tamm C. Approaches to the Synthesis of Cytochalasans Part9. A versatile concept leading to all structural types of cytochalasans. Helv Chim Acta 1990. [DOI: 10.1002/hlca.19900730113] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
49
|
Buchholz S, Harms K, Marsch M, Massa W, Boche G. Modell eines solvens-verbrückten Ionenpaares mit NH⃛C-Wasserstoffbrücken zwischen Amin und Carbanion – Kristallstruktur von [Fluorenyllithium·2Ethylendiamin]∞. Angew Chem Int Ed Engl 1989. [DOI: 10.1002/ange.19891010109] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
50
|
Buchholz S, Harms K, Marsch M, Massa W, Boche G. Model of a Solvent-Shared Ion Pair with N?H?C Hydrogen Bonds between Amine and Carbanion?Crystal Structure of [Fluorenyllithium�2 Ethylenediamine]? ACTA ACUST UNITED AC 1989. [DOI: 10.1002/anie.198900721] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|