1
|
Haufe G. Synthesis and application of pentafluorosulfanylation reagents and derived aliphatic SF5-containing building blocks. Tetrahedron 2022. [DOI: 10.1016/j.tet.2022.132656] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
|
2
|
Dudziński P, Husstedt WS, Matsnev AV, Thrasher JS, Haufe G. Synthesis and [3,3]-sigmatropic rearrangements of 5-(pentafluorosulfanyl)-pent-3-en-2-ol, its homologues, and trifluoromethyl analogues. Org Biomol Chem 2021; 19:5607-5623. [PMID: 34100055 DOI: 10.1039/d1ob00870f] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of aliphatic (pentafluoro-λ6-sulfanyl)(SF5)-substituted compounds is more challenging than that of the related CF3-substituted analogues. Previous investigations of [3,3]-sigmatropic rearrangements of γ-SF5-substituted allylic alcohols failed to yield 3-SF5-substituted carboxylic acid derivatives. Herein, we present the synthesis of a series of 1-SF5-alk-1-en-3-ols and our efforts to apply them in Johnson-Claisen, ester enolate-Claisen, and Ireland-Claisen rearrangements. Unfortunately, these reactions failed to include the 1-SF5-substituted 1,2-double bond, although successful reactions of analogous CF3-allylic alcohols were reported. Further experiments revealed that bulkiness rather than electronic properties of the SF5 group prevented [3,3]-sigmatropic rearrangements. Indeed, the introduction of a competing second vinyl group into the system (1-SF5-penta-1,4-dien-3-ol) confirmed that a Johnson-Claisen rearrangement was successful (92% yield of methyl 7-SF5-hepta-4,6-dienoate) with incorporation of the unsubstituted 4,5-double bond while the 1-SF5-substituted 1,2-double bond remained unchanged. Efforts to apply 1-(SF5CF2)-substituted 1,2-double bond systems, which are similar to CF3 analogues in steric requirements, in Johnson-Claisen or ester enolate-Claisen rearrangements failed because of the instability of the SF5CF2 substituent under various reaction conditions. On the other hand, when the SF5 group was separated from the reaction center by a CH2 group instead (5-SF5-pent-3-en-2-ol), Johnson-Claisen rearrangements using six orthoesters provided the target 2-substituted 3-(CH2SF5)-hex-4-enoates in 55-76% yields as ∼1 : 1 mixtures of diastereomers. As an example to demonstrate the utility of these products, methyl 3-(CH2SF5)-hex-4-enoate was reduced, and the formed alcohol was oxidized to the aldehyde. Finally, initial experiments showed that the synthetic sequence developed for SF5 compounds is also applicable for analogous CF3-substituted allylic alcohols (5-CF3-pent-3-en-2-ol) and their Johnson-Claisen rearrangement.
Collapse
Affiliation(s)
- Piotr Dudziński
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, D-48149 Münster, Germany.
| | - Wibke S Husstedt
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, D-48149 Münster, Germany.
| | - Andrej V Matsnev
- Department of Chemistry, Advanced Materials Research Laboratory, Clemson University, 91 Technology Drive, Anderson, South Carolina 29625, USA
| | - Joseph S Thrasher
- Department of Chemistry, Advanced Materials Research Laboratory, Clemson University, 91 Technology Drive, Anderson, South Carolina 29625, USA
| | - Günter Haufe
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, D-48149 Münster, Germany.
| |
Collapse
|
3
|
Intramolecular construction of trifluoromethyl group by the palladium-catalyzed reaction of 2,3,3-trifluoroallylic carbonates with O -nucleophiles. Tetrahedron 2018. [DOI: 10.1016/j.tet.2018.02.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
|
4
|
Belot V, Farran D, Jean M, Albalat M, Vanthuyne N, Roussel C. Steric Scale of Common Substituents from Rotational Barriers of N-(o-Substituted aryl)thiazoline-2-thione Atropisomers. J Org Chem 2017; 82:10188-10200. [DOI: 10.1021/acs.joc.7b01698] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vincent Belot
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| | - Daniel Farran
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| | - Marion Jean
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| | - Muriel Albalat
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| | - Nicolas Vanthuyne
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| | - Christian Roussel
- Aix Marseille Univ, CNRS, Centrale Marseille,
iSm2, Marseille, France
| |
Collapse
|
5
|
Isobe SI, Terasaki S, Hanakawa T, Mizuno S, Kawatsura M. Ruthenium-catalyzed regioselective allylic amination of 2,3,3-trifluoroallylic carbonates. Org Biomol Chem 2017; 15:2938-2946. [PMID: 28290580 DOI: 10.1039/c7ob00514h] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
We demonstrated the ruthenium-catalyzed allylic amination of 2,3,3-trifluoroallylic carbonates with several types of amines. The reactions proceeded with several types of amines, and succeeded in obtaining polyfluorinated terminal alkenes possessing branched allylic amines as a single regioisomer.
Collapse
Affiliation(s)
- Shin-Ichi Isobe
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
| | - Shou Terasaki
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
| | - Taisyun Hanakawa
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
| | - Shota Mizuno
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
| | - Motoi Kawatsura
- Department of Chemistry, College of Humanities & Sciences, Nihon University, Sakurajosui, Setagaya-ku, Tokyo 156-8550, Japan.
| |
Collapse
|
6
|
Dreier AL, Beutel B, Mück-Lichtenfeld C, Matsnev AV, Thrasher JS, Haufe G. Synthesis of α-(Pentafluorosulfanyl)- and α-(Trifluoromethyl)-Substituted Carboxylic Acid Derivatives by Ireland–Claisen Rearrangement. J Org Chem 2017; 82:1638-1648. [DOI: 10.1021/acs.joc.6b02805] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Anna-Lena Dreier
- Organisch-Chemisches
Institut, Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | - Bernd Beutel
- Organisch-Chemisches
Institut, Universität Münster, Corrensstraße 40, 48149 Münster, Germany
| | | | - Andrej V. Matsnev
- Department
of Chemistry, Advanced Materials Research Laboratory, Clemson University, 91 Technology Drive, Anderson, South Carolina 29625, United States
| | - Joseph S. Thrasher
- Department
of Chemistry, Advanced Materials Research Laboratory, Clemson University, 91 Technology Drive, Anderson, South Carolina 29625, United States
| | - Günter Haufe
- Organisch-Chemisches
Institut, Universität Münster, Corrensstraße 40, 48149 Münster, Germany
- Cells-in-Motion
Cluster of Excellence, Universität Münster, Waldeyerstraße
15, 48149 Münster, Germany
| |
Collapse
|
7
|
Ikeda K, Futamura T, Hanakawa T, Minakawa M, Kawatsura M. Palladium-catalyzed enantioselective allylic alkylation of trifluoromethyl group substituted racemic and acyclic unsymmetrical 1,3-disubstituted allylic esters with malonate anions. Org Biomol Chem 2016; 14:3501-5. [DOI: 10.1039/c6ob00449k] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We accomplished the enantioselective allylic alkylation of racemic and acyclic unsymmetrical 1,3-disubstituted allylic esters with a malonate anion by DYKAT.
Collapse
Affiliation(s)
- Kazunori Ikeda
- Department of Chemistry
- College of Humanities & Sciences
- Nihon University
- Tokyo 156-8550
- Japan
| | - Takashi Futamura
- Department of Chemistry
- College of Humanities & Sciences
- Nihon University
- Tokyo 156-8550
- Japan
| | - Taisyun Hanakawa
- Department of Chemistry
- College of Humanities & Sciences
- Nihon University
- Tokyo 156-8550
- Japan
| | - Maki Minakawa
- Department of Chemistry
- College of Humanities & Sciences
- Nihon University
- Tokyo 156-8550
- Japan
| | - Motoi Kawatsura
- Department of Chemistry
- College of Humanities & Sciences
- Nihon University
- Tokyo 156-8550
- Japan
| |
Collapse
|
8
|
Ichikawa T, Kawasaki-Takasuka T, Yamada S, Yamazaki T, Kubota T. Construction of chiral trifluoromethylated materials by combination of stereochemically predictable SN2′ reaction and Ireland-Claisen rearrangement. J Fluor Chem 2013. [DOI: 10.1016/j.jfluchem.2012.10.013] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
9
|
Bizet V, Pannecoucke X, Renaud JL, Cahard D. Synthesis of β-CF3 ketones from trifluoromethylated allylic alcohols by ruthenium catalyzed isomerization. J Fluor Chem 2013. [DOI: 10.1016/j.jfluchem.2013.01.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
|
10
|
Bizet V, Pannecoucke X, Renaud JL, Cahard D. Ruthenium-Catalyzed Redox Isomerization of Trifluoromethylated Allylic Alcohols: Mechanistic Evidence for an Enantiospecific Pathway. Angew Chem Int Ed Engl 2012; 51:6467-70. [DOI: 10.1002/anie.201200827] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Indexed: 11/12/2022]
|
11
|
Bizet V, Pannecoucke X, Renaud JL, Cahard D. Ruthenium-Catalyzed Redox Isomerization of Trifluoromethylated Allylic Alcohols: Mechanistic Evidence for an Enantiospecific Pathway. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201200827] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
|
12
|
Mizota I, Tanaka K, Shimizu M. Synthesis of γ,δ-unsaturated quaternary α-alkylamino acids using umpolung reaction and Claisen rearrangement. Tetrahedron Lett 2012. [DOI: 10.1016/j.tetlet.2012.01.133] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
|
13
|
Nie J, Guo HC, Cahard D, Ma JA. Asymmetric construction of stereogenic carbon centers featuring a trifluoromethyl group from prochiral trifluoromethylated substrates. Chem Rev 2010; 111:455-529. [PMID: 21117644 DOI: 10.1021/cr100166a] [Citation(s) in RCA: 876] [Impact Index Per Article: 62.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jing Nie
- Department of Chemistry, Tianjin University, China
| | | | | | | |
Collapse
|
14
|
Lam YH, Stanway SJ, Gouverneur V. Recent progress in the use of fluoroorganic compounds in pericyclic reactions. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.08.005] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
15
|
Kumamoto H, Haraguchi K, Ida M, Nakamura KT, Kitagawa Y, Hamasaki T, Baba M, Matsubayashi SS, Tanaka H. Synthesis of (±)-4′-ethynyl-5′,5′-difluoro-2′,3′-dehydro-3′-deoxy- carbocyclic thymidine: a difluoromethylidene analogue of promising anti-HIV agent Ed4T. Tetrahedron 2009. [DOI: 10.1016/j.tet.2009.06.095] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
16
|
Michaux J, Niel G, Campagne JM. Stereocontrolled routes to β,β′-disubstituted α-amino acids. Chem Soc Rev 2009; 38:2093-116. [DOI: 10.1039/b812116h] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
|
17
|
Xu J, Qiu XL, Qing FL. Understanding the mechanism of Pd-catalyzed allylic substitution of the cyclic difluorinated carbonates. Beilstein J Org Chem 2008; 4:18. [PMID: 18941489 PMCID: PMC2486488 DOI: 10.3762/bjoc.4.18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2008] [Accepted: 05/15/2008] [Indexed: 11/23/2022] Open
Abstract
We present a mechanistic investigation of Pd-catalyzed allylic substitution of cyclic gem-difluorinated carbonates 1 and 4, previously employed in the synthesis of 3',3'-difluoro-2'-hydroxymethyl-4',5'-unsaturated carbocyclic nucleosides in 17 steps. The substitution features a reversal of regioselectivity caused by fluorine.
Collapse
Affiliation(s)
- Jun Xu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
| | - Xiao-Long Qiu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
| | - Feng-Ling Qing
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China
- College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| |
Collapse
|
18
|
Konno T, Tanaka T, Miyabe T, Morigaki A, Ishihara T. A first high enantiocontrol of an asymmetric tertiary carbon center attached with a fluoroalkyl group via Rh(I)-catalyzed conjugate addition reaction. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.01.122] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
19
|
Yang YY, Xu J, You ZW, Xu XH, Qiu XL, Qing FL. Synthesis of 3‘,3‘-Difluoro-2‘- hydroxymethyl-4‘,5‘-Unsaturated Carbocyclic Nucleosides. Org Lett 2007; 9:5437-40. [DOI: 10.1021/ol7023955] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Yan-Yan Yang
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| | - Jun Xu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| | - Zheng-Wei You
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| | - Xiu-hua Xu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| | - Xiao-Long Qiu
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| | - Feng-Ling Qing
- Key Laboratory of Organofluorine Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, China, and College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 2999 North Renmin Lu, Shanghai 201620, China
| |
Collapse
|
20
|
|
21
|
Affiliation(s)
- Ana M Martín Castro
- Departamento de Química Orgánica, Universidad Autónoma de Madrid, Cantoblanco, 28049 Madrid, Spain.
| |
Collapse
|
22
|
Kaiser J, Kinderman SS, van Esseveldt BCJ, van Delft FL, Schoemaker HE, Blaauw RH, Rutjes FPJT. Synthetic applications of aliphatic unsaturated α-H-α-amino acids. Org Biomol Chem 2005; 3:3435-67. [PMID: 16172678 DOI: 10.1039/b507973j] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
This article provides an overview of the literature concerning synthetic applications of unsaturated aliphatic amino acids in the period May 2000 to December 2004.
Collapse
Affiliation(s)
- Jasper Kaiser
- Radboud University Nijmegen, Institute for Molecules and Materials, Toernooiveld 1, NL-6525 ED Nijmegen, The Netherlands
| | | | | | | | | | | | | |
Collapse
|
23
|
Funabiki K, Hara N, Nagamori M, Shibata K, Matsui M. Johnson–Claisen rearrangement of γ-fluoro-γ-(di- or tri-fluoromethyl)allyl alcohols affording stereoselective access to β-fluoro-β-di- or tri-fluoromethylated γ,δ-unsaturated carboxylic acid esters. J Fluor Chem 2003. [DOI: 10.1016/s0022-1139(03)00108-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
24
|
Schleusner M, Gais HJ, Koep S, Raabe G. Highly selective addition of chiral, sulfonimidoyl substituted bis(allyl)titanium complexes to N-sulfonyl alpha-imino esters: asymmetric synthesis of gamma,delta-unsaturated alpha-amino acids bearing a chiral, electron-withdrawing nucleofuge at the delta-position. J Am Chem Soc 2002; 124:7789-800. [PMID: 12083933 DOI: 10.1021/ja0201799] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Selective addition of the chiral, sulfonimidoyl substituted bis(allyl)titanium complexes 5a-d, which are configurationally labile in regard to the Calpha-atoms, to N-toluenesulfonyl (Ts)-, N-2-trimethylsilylethanesulfonyl (SES)-, and N-tert-butylsulfonyl (Bus) alpha-imino ester (9a-c) in the presence of Ti(OiPr)(4) and ClTi(OiPr)(3) afforded with high regio- and diastereoselectivities in good yields the (syn, E)-configured beta-alkyl-gamma,delta-unsaturated alpha-amino acid derivatives 2a-g, which carry a chiral, electron-withdrawing nucleofuge at the delta-position and a cyclohexyl, an isopropyl, a phenyl, and a methyl group at the beta-position. Addition of the cyclic bis(allyl)titanium complex 14 to N-Bus alpha-imino ester 9c afforded with similar high regio- and diastereoselectivities the (E)- and (Z)-configured amino acid derivatives (E)-8 and (Z)-8. Reaction of complexes 5a-d with alpha-imino esters 9a-c in the presence of Ti(OiPr)(4) occurs stepwise to give first the mono(allyl)titanium complexes containing 2a-g as ligands, which react in the presence of ClTi(OiPr)(3) with a second molecule of 9a-c with formation of two molecules of 2a-g. Formation of (S,R,E)-configured homoallylic amines 2a-g entails Si,Re,E processes of alpha-imino esters 9a-c with the (R,R)-configured bis(allyl)titanium complexes (R,R)-5a-d and (R)-configured mono(allyl)titanium complexes (R)-17a-d, both of which are most likely in rapid equilibrium with their (S,S)-diastereomers and (S)-diastereomers, respectively. Interestingly, in the reaction of 5a-d with aldehydes, the (S,S)-configured complexes (S,S)-5a-d are the ones which react faster. Reaction of the N-titanated amino acid derivatives Ti-2a and Ti-2b with N-Ts alpha-imino ester 9a led to the highly diastereoselective formation of imidazolidinones 15a and 15b, respectively. Cleavage of the sulfonamide group of the N-Bus amino acid derivative 2d with CF(3)SO(3)H gave quantitatively the sulfonimidoyl functionalized amino acid H-2d. A Ni-catalyzed cross-coupling reaction of the amino acid derivative 2e with ZnPh(2) led to a substitution of the sulfonimidoyl group by a phenyl group and furnished the enantiomerically pure protected alpha-amino acid Bus-1. Two new N-sulfonyl alpha-imino esters, the SES and the Bus alpha-imino esters 9b and 9c, respectively, have been synthesized from the corresponding sulfonamides by the Kresze method in medium to good yields. The N-SES alpha-imino ester 9b and the N-Bus alpha-imino ester 9c should find many synthetic applications, in particular, in cases where the N-Ts alpha-imino ester 9a had been used before.
Collapse
Affiliation(s)
- Marcel Schleusner
- Institut für Organische Chemie der Rheinisch-Westfälischen Technischen Hochschule (RWTH) Aachen, Professor-Pirlet-Strasse 1, D-52056 Aachen, Germany
| | | | | | | |
Collapse
|