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Ghosh AK, Basu AJ, Hsu CS, Yadav M. Asymmetric 1,2-Carbamoyl Rearrangement of Lithiated Chiral Oxazolidine Carbamates and Diastereoselective Synthesis of α-Hydroxy Amides. Chemistry 2022; 28:e202200941. [PMID: 35587995 PMCID: PMC9356997 DOI: 10.1002/chem.202200941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2022] [Indexed: 11/11/2022]
Abstract
Asymmetric 1,2-carbamoyl rearrangement of lithiated 2-alkenyl carbamates has been investigated. Deprotonation of chiral 2-alkenyl oxazolidine carbamates with sec-butyllithium in ether at -78 °C followed by warming of the resulting 1-lithio-2-alkenyl derivatives to room temperature resulted in 1,2-carbamoyl rearrangement to provide α-hydroxy amides. The rearrangement proceeded with excellent diastereoselectivity and in good to excellent isolated yield of the α-hydroxy amide derivatives. The substrate scope of the reaction was investigated with a variety of 2-alkenyl and benzyl oxazolidine carbamates. A stereochemical model is provided to explain the stereochemical outcome associated with the rearrangement. Acid-catalyzed removal of the chiral oxazolidine afforded α-hydroxy acid in high optical purity.
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Affiliation(s)
- Arun K Ghosh
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
| | - Amartyo J Basu
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
| | - Che-Sheng Hsu
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
| | - Monika Yadav
- Department of Chemistry and Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, 560 Oval Dr., West Lafayette, IN 47907, USA
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2
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Bojaryn K, Hirschhäuser C. Transition Metal Catalyst Free Synthesis of Olefins from Organoboron Derivatives**. Chemistry 2022; 28:e202104125. [PMID: 35137987 PMCID: PMC9303902 DOI: 10.1002/chem.202104125] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2021] [Indexed: 11/29/2022]
Abstract
Stereoselective preparation of highly substituted olefins is still a severe challenge that requires well defined elimination precursors. Organoboron chemistry is particularly suited for the preparation of molecules with adjacent stereocenters. As organo boron substrates with leaving groups in β‐position can undergo stereospecific syn‐ or anti‐elimination, this chemistry harbors great potential for the synthesis of complex olefins. In recent years three main strategies emerged, which differ in their approach to the β‐functionalized organoboron elimination precursor. (i) Stereoselective preparation of such elimination precursor can be achieved by addition of a boron‐stabilized anion (d1) to an aldehyde or ketone (a1) or diastereoselective 1,3‐rearrangement of suitable boron‐ate‐complexes. Stereospecific methods rely either on (ii) diastereospecific 1,2‐metalate rearrangement of boron‐ate‐complexes that involve opening of appropriate heterocycles or (iii) addition of chiral carbenoids (d1*) to chiral boronates (a1*) with a leaving group in α‐position.
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Affiliation(s)
- K. Bojaryn
- Institut für Organische Chemie Universität Duisburg-Essen Universitätsstraße 7 45141 Essen Germany
| | - C. Hirschhäuser
- Institut für Organische Chemie Universität Duisburg-Essen Universitätsstraße 7 45141 Essen Germany
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3
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Yuan W, Shang Z, Qiang X, Tan Z, Deng Y. Synthesis of pterostilbene and resveratrol carbamate derivatives as potential dual cholinesterase inhibitors and neuroprotective agents. RESEARCH ON CHEMICAL INTERMEDIATES 2013. [DOI: 10.1007/s11164-012-1003-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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4
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Sakakura A, Yamada H, Ishihara K. α-Heterosubstituted β-Alkylacroleins as Useful Multisubstituted Dienophiles for Enantioselective Diels-Alder Reactions. ASIAN J ORG CHEM 2012. [DOI: 10.1002/ajoc.201200054] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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5
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Pulis AP, Aggarwal VK. Synthesis of Enantioenriched Tertiary Boronic Esters from Secondary Allylic Carbamates. Application to the Synthesis of C30 Botryococcene. J Am Chem Soc 2012; 134:7570-4. [DOI: 10.1021/ja303022d] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Alexander P. Pulis
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
| | - Varinder K. Aggarwal
- School of Chemistry, University of Bristol, Cantock’s Close, Bristol,
BS8 1TS, United Kingdom
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6
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Cui Y, Floreancig PE. Synthesis of sulfur-containing heterocycles through oxidative carbon-hydrogen bond functionalization. Org Lett 2012; 14:1720-3. [PMID: 22420412 DOI: 10.1021/ol3002877] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Vinyl sulfides react rapidly and efficiently with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to form α,β-unsaturated thiocarbenium ions through oxidative carbon-hydrogen bond cleavage. These electrophiles couple with appended π-nucleophiles to yield sulfur-containing heterocycles through carbon-carbon bond formation. Several nucleophiles are compatible with the procedure, and the reactions generally proceed through readily predictable transition states.
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Affiliation(s)
- Yubo Cui
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, USA
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Cooksey JP, Ford R, Kocieński PJ, Pelotier B, Pons JM. A synthesis of (−)-ebelactones A and B. Tetrahedron 2010. [DOI: 10.1016/j.tet.2010.05.072] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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8
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Chen YL, Hoppe D. 1-(N,N-diisopropylcarbamoyloxy)-1-tosyl-1-alkenes--a2d1 synthons via tandem umpolung. J Org Chem 2009; 74:4188-94. [PMID: 19413297 DOI: 10.1021/jo900347s] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
1-(N,N-diisopropylcarbamoyloxy)-1-tosyl-alkenes have been developed as an a(2)d(1) synthon via tandem umpolung. Upon addition of Grignard reagents and further quench by carbonyl compounds, this synthon produces alpha,alpha'-branched-alpha'-oxygenated ketones. Strategically, this widely applicable method installs respectively a carbanion unit and a carbonyl unit formally onto the alpha-carbon and the carbonyl center of an aldehyde in one-pot.
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Affiliation(s)
- Yue-Lei Chen
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, 48149 Münster, Germany.
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Becker J, Fröhlich R, Salorinne K, Hoppe D. Asymmetric Homoaldol Reactions with Cyclohex-2-enylN,N-Diisopropylcarbamate: Kinetic Resolution, Elucidation of the Stereochemical Course and Applications in the Synthesis of Hexahydroisobenzofuran-4-(1H)-ones. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700219] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bou Chedid R, Fröhlich R, Wibbeling B, Hoppe D. Enantioselective γ-Deprotonation of Alkyl-SubstitutedO-1,3-Butadien-2-yl Carbamates and Regioselective Asymmetric Homoaldol Reaction. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700131] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Becker J, Fröhlich R, Kataeva O, Hoppe D. Stereoselective Synthesis of Hexahydroisobenzofuran-4(1H)-ones from Chiral Substituted Cyclohex-2-enyl Carbamates via Asymmetric Homoaldol Reaction and THF Cyclocondensation. European J Org Chem 2007. [DOI: 10.1002/ejoc.200700220] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Chedid RB, Fröhlich R, Hoppe D. Asymmetric γ-Deprotonation and Homoaldol Reaction of 1,3-Dien-2-yl Carbamates: Stereo- and Regiochemistry. Org Lett 2006; 8:3061-4. [PMID: 16805552 DOI: 10.1021/ol061005p] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Lithium compounds 7 are configurationally stable intermediates obtained by deprotonation of 1,3-dien-2-yl carbamates 6 with n-butyllithium/(-)-sparteine with a high degree of enantiotopic differentiation at the gamma-position. They react with electrophiles regioselectively giving highly enantioenriched products. Starting with different isomers or changing the double-bond geometries in 6 leads to either of the enantiomers.
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Affiliation(s)
- Roland Bou Chedid
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Germany
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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]
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14
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Hoppe D, Krämer T. α-Deprotonation of an α-Chiral 2-Alkenylcarbamate with Retention and Lithium-Titanium Exchange with Inversion- the Homoaldol Reaction with 1,3-Chirality Transfer. ACTA ACUST UNITED AC 2003. [DOI: 10.1002/anie.198601601] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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15
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Efficient preparation of (Z)-alkenyl derivatives from (Z)-vinyl (N,N-diisopropyl)carbamate via Ni-catalysed coupling reactions. Tetrahedron Lett 2003. [DOI: 10.1016/s0040-4039(03)01804-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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16
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Whisler MC, Beak P. Synthetic applications of lithiated N-Boc allylic amines as asymmetric homoenolate equivalents. J Org Chem 2003; 68:1207-15. [PMID: 12585857 DOI: 10.1021/jo0260084] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Lithiation of N-(Boc)-N-(p-methoxyphenyl) allylic amines in the presence of (-)-sparteine provides asymmetric homoenolate equivalents which react with electrophiles to provide highly enantioenriched enecarbamates. Acidic hydrolysis of the enecarbamates can provide the corresponding beta-substituted aldehydes. A synthetic sequence that involves a stereocontrolled intramolecular nitrone-olefin dipolar cycloaddition has been developed for the preparation of enantioenriched 2-formyl-4-phenyl-1-aminocyclopentanes from one beta-allyl-substituted aldehyde. Further manipulations allow access to an enantioenriched beta-lactam. In another synthetic sequence, transmetalation of the lithiated intermediates and reactions with aldehyde electrophiles can be controlled to afford highly enantioenriched anti homoaldol products. Use of an anti aldehyde homoaldol product as the chiral electrophile in an iterative reaction provides a double homoaldol product containing four stereogenic centers with high diastereoselectivity and enantioselectivity. Reaction pathways are proposed to account for the observed products.
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Affiliation(s)
- Marna C Whisler
- Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Avenue, Urbana, Illinois 61801, USA
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17
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Enantioselective Synthesis by Lithiation Adjacent to Oxygen and Electrophile Incorporation. TOP ORGANOMETAL CHEM 2003. [DOI: 10.1007/3-540-36117-0_4] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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18
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Marr F, Fröhlich R, Wibbeling B, Diedrich C, Hoppe D. The Synthesis and Configurational Stability of Enantioenriched α-Thioallyllithium Compounds and the Stereochemical Course of Their Electrophilic Substitution. European J Org Chem 2002. [DOI: 10.1002/1099-0690(200209)2002:17<2970::aid-ejoc2970>3.0.co;2-j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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19
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Grimaud L, de Mesmay R, Prunet J. Diastereoselective synthesis of protected syn 1,3-diols: preparation of the C16-C24 portion of Dolabelides. Org Lett 2002; 4:419-21. [PMID: 11820894 DOI: 10.1021/ol017122w] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We have designed a new method to make synthons encompassing a protected syn 1,3-diol motif and an aldehyde alpha to the 1,3-dioxane ring. An additional stereocenter was also created, potentially leading to stereochemically defined 1,2,4-triols. This method was successfully applied to the synthesis of the C16-C24 portion of Dolabelides.
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Affiliation(s)
- Laurence Grimaud
- Laboratoire Chimie et Procédés, Ecole Nationale Supérieure des Techniques Avancées, 32 boulevard Victor, F-75015 Paris, France
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20
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Özlügedik M, Kristensen J, Wibbeling B, Fröhlich R, Hoppe D. Nonracemic, Chiral Homoenolate Reagents Derived from (Cycloalk-1-enyl)methyl Carbamates and Evaluation of Their Configurational Stabilities. European J Org Chem 2002. [DOI: 10.1002/1099-0690(20022)2002:3<414::aid-ejoc414>3.0.co;2-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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21
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Enantioenriched acid, ester, and ketone β-phenyl homoenolate synthetic equivalents from N-Boc-N-(p-methoxyphenyl)cinnamylamine. Tetrahedron Lett 2000. [DOI: 10.1016/s0040-4039(00)01663-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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22
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Deiters A, Hoppe D. Chiral induzierte, mit einer Eliminierung gekoppelte Lithium-En-Reaktion – Synthese von (+)-(3R,4R)-1,2-Dihydromultifiden. Angew Chem Int Ed Engl 1999. [DOI: 10.1002/(sici)1521-3757(19990215)111:4<529::aid-ange529>3.0.co;2-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Behrens K, Fröhlich R, Meyer O, Hoppe D. Enantioselective Lithiation and Substitution of (E)-CinnamylN,N-Diisopropylcarbamate through Use of (−)-Sparteine Complexes. European J Org Chem 1998. [DOI: 10.1002/(sici)1099-0690(199811)1998:11<2397::aid-ejoc2397>3.0.co;2-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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24
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Hoppe D, Hense T. Enantioselektive Synthese mit Lithium/(−)-Spartein-Carbanion-Paaren. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971092105] [Citation(s) in RCA: 200] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Ahlbrecht H, Kramer A. Chiral Homoenolate Equivalents, V. Hydroxylakylation of Lithiated 3-[(S)-2-(Methoxymethyl)pyrrolidino]-1,3-diphenylpropene – An Asymmetric Homoaldol Reaction. ACTA ACUST UNITED AC 1996. [DOI: 10.1002/cber.19961291004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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27
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Mason PH, Emslie ND. Preparation of Substituted Vinylsilanes from Cinnamyl Carbamates. SYNTHETIC COMMUN 1996. [DOI: 10.1080/00397919608003513] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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28
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Mason PH, Yoell DK, Frances van Staden L, Emslie ND. Bis-Silylation of N,N-Diethylbenzyl and Cinnamyl Carbamates. SYNTHETIC COMMUN 1995. [DOI: 10.1080/00397919508013854] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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29
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Carstens A, Hoppe D. Generation of a configurationally stable, enantioenriched α-oxy-α-methylbenzyllithium: Stereodivergence of its electrophilic substitution. Tetrahedron 1994. [DOI: 10.1016/s0040-4020(01)90461-2] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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30
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Hoffmann RW, Brumm K, Bewersdorf M, Mikolaiski W, Kusche A. Chiral Organometallic Reagents, IX. On the Origins of the Diastereoselectivity in the Bromine/Lithium Exchange of 3–Alkoxy–1,1–dibromoalkanes. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/cber.19921251220] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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31
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Zschage O, Schwark JR, Krämer T, Hoppe D. Enantiomerically enriched 1-(N,N-diisopropylcarbamoyloxy)-1,3-dimethylallyllithium: stereochemistry of the stannylation, titanation, and the homoaldol reaction. Tetrahedron 1992. [DOI: 10.1016/s0040-4020(01)86586-8] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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32
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Sparteine complexes of lithiated primary O-2-alkenyl carbamates stereochemistry of the lithium-titanium exchange and application for the synthesis of enantiomerically enriched γ-lactones. Tetrahedron 1992. [DOI: 10.1016/0040-4020(92)80016-9] [Citation(s) in RCA: 74] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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33
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Peschke B, Lüßmann J, Hoppe D, Dyrbusch Z. Diastereo- and enantioselective synthesis of 1,2:5,6-diepoxy-4-hydroxyalkyl carbamates. – regioselective ring opening and their transformation into doublyC-branched deoxy sugar analogues. ACTA ACUST UNITED AC 1992. [DOI: 10.1002/cber.19921250620] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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34
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Calderón A, Font J, de March P. Bromine addition to α-(1-hydroxyalkyl)- and α-(1-alkoxy-alkyl)-α,β-unsaturated esters: an approach to hydroxyfimbrolide and bromobeckerelide. Tetrahedron 1992. [DOI: 10.1016/s0040-4020(01)89031-1] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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35
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Hoffmann RW, Jens Wolff J. Stereoselective Synthesis of Alcohols, XXXVII. Origins of Stereoselectivity in Reactions of α-Substituted Allylboronates with Aldehydes. ACTA ACUST UNITED AC 1991. [DOI: 10.1002/cber.19911240323] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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36
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37
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Zschage O, Schwark JR, Hoppe D. Herstellung eines enantiomerenangereicherten Allyllithium-Derivates durch Deprotonierung unter kinetischer Racematspaltung. Angew Chem Int Ed Engl 1990. [DOI: 10.1002/ange.19901020334] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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38
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Hoppe I, Hoppe D, Wolff C, Egert E, Herbst R. 3-Arylsulfonyloxazolidine als chirale Template; asymmetrische Synthese von 2-substituierten 2-Hydroxycyclohexancarbaldehyden aus 2-Hydroxymethylencyclohexanon. Angew Chem Int Ed Engl 1989. [DOI: 10.1002/ange.19891010115] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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39
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Hoppe I, Hoppe D, Wolff C, Egert E, Herbst R. 3-Arylsulfonyloxazolidines as Chiral Templates; Asymmetric Synthesis of 2-Substituted 2-Hydroxycyclohexanecarbaldehydes from 2-Hydroxymethylenecyclohexanone. ACTA ACUST UNITED AC 1989. [DOI: 10.1002/anie.198900671] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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40
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Hoppe D, Zschage O. Asymmetric Homoaldol Reaction by Enantioselective Lithiation of a Prochiral 2-Butenyl Carbamate. ACTA ACUST UNITED AC 1989. [DOI: 10.1002/anie.198900691] [Citation(s) in RCA: 98] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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41
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Asymmetrische Homoaldol-Reaktion durch enantioselektive Lithiierung eines prochiralen 2-Butenylcarbamats. Angew Chem Int Ed Engl 1989. [DOI: 10.1002/ange.19891010116] [Citation(s) in RCA: 67] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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42
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Studies toward the total synthesis of 1-oxacephalosporins 3: synthesis of a (±)-trans-7-benzoylamino-3-carbamoyloxymethyl-1-oxa-3-cepheh-3-carboxylate from 1,3-dihydroxyacetone. Tetrahedron 1989. [DOI: 10.1016/0040-4020(89)80100-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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43
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Reggelin M, Tebben P, Hoppe D. Synthesis and deprotonation of 1-(p-toluenesulfonyl)-2-al-kenyl carbamates. Dichotomous achiral d1 and chiral d3 reagents for carbonyl addition directed by metal exchange. Tetrahedron Lett 1989. [DOI: 10.1016/s0040-4039(00)99157-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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44
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Hoffmann RW, Dresely S, Lanz JW. Stereoselective Synthesis of Alcohols, XXVII. Addition of (α-Chlorocrotyl)boronates to Aldehydes. ACTA ACUST UNITED AC 1988. [DOI: 10.1002/cber.19881210826] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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45
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46
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Hoppe D, Tarara G, Wilckens M, Jones PG, Schmidt D, Stezowski JJ. Enantioselektive Synthese von Methylfuranosiden unnatürlicher 3,6-Didesoxy-3-methyl-aldohexosen aus Milchsäureestern durch Homoaldol-Reaktion. Angew Chem Int Ed Engl 1987. [DOI: 10.1002/ange.19870991033] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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47
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Hoppe D, Gonschorrek C, Schmidt D, Egert E. Highly regio- and syn-diastereoselective synthesis of 4-hydroxy-1,2-alkadienylcarbamates from α-titanatedl 2-alkynylcarbamates and aldehydes1,2. Tetrahedron 1987. [DOI: 10.1016/s0040-4020(01)81651-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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48
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Krämer T, Hoppe D. Reagent-controlled enantioselective homoaldol reaction with chiral 1-oxyallyllithium derivatives. Enantio-divergent tuning by achiral titanium reagents. Tetrahedron Lett 1987. [DOI: 10.1016/s0040-4039(00)95614-4] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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49
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Hoppe D, Krämer T. α-Deprotonierung eines α-chiralen 2-Alkenylcarbamats unter Retention und Lithium-Titan-Austausch unter Inversion - zur Homoaldol-Reaktion unter 1,3-Chiralitätsübertragung. Angew Chem Int Ed Engl 1986. [DOI: 10.1002/ange.19860980212] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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50
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van Hülsen E, Hoppe D. Completely stereoselective synthesis of all four stereoisomeric 1-carbamoyloxy-1,3-alkadienes via anti-diastereoselective homoaldol reaction from aldehydes and a single carbon-three-unit. Tetrahedron Lett 1985. [DOI: 10.1016/s0040-4039(00)61897-x] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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