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Aguiar AR, Alvarenga ES, Oliveira RP, Carneiro VMT, Moura LG. Syntheses of epoxides, and structural analysis of (E)N-hexyl-3-(trans-3-methyloxiran-2-yl)prop-2-enamide by spectroscopic techniques and DFT calculations. J Mol Struct 2018. [DOI: 10.1016/j.molstruc.2018.04.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Unexpected decarboxamidation of α-arylsulfonyl Weinreb amides by Grignard reagents: Synthesis of α-disubstituted arylsulfones. Chem Res Chin Univ 2017. [DOI: 10.1007/s40242-017-6371-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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4
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Banerjee S, Sinha S, Pradhan P, Caruso A, Liebowitz D, Parrish D, Rossi M, Zajc B. Regiospecifically Fluorinated Polycyclic Aromatic Hydrocarbons via Julia-Kocienski Olefination and Oxidative Photocyclization. Effect of Fluorine Atom Substitution on Molecular Shape. J Org Chem 2016; 81:3983-93. [PMID: 27009471 PMCID: PMC4874880 DOI: 10.1021/acs.joc.5b02580] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A modular synthesis of regiospecifically fluorinated polycyclic aromatic hydrocarbons (PAHs) is described. 1,2-Diarylfluoroalkenes, synthesized via Julia-Kocienski olefination (70-99% yields), were converted to isomeric 5- and 6-fluorobenzo[c]phenanthrene, 5-and 6-fluorochrysene, and 9- and 10-benzo[g]chrysene (66-83% yields) by oxidative photocyclization. Photocyclization to 6-fluorochrysene proceeded more slowly than conversion of 1-styrylnaphthalene to chrysene. Higher fluoroalkene dilution led to a more rapid cyclization. Therefore, photocyclizations were performed at higher dilutions. To evaluate the effect of fluorine atom on molecular shapes, X-ray data for 5- and 6-fluorobenzo[c]phenanthrene, 6-fluorochrysene, 9- and 10-fluorobenzo[g]chrysene, and unfluorinated chrysene as well as benzo[g]chrysene were obtained and compared. The fluorine atom caused a small deviation from planarity in the chrysene series and decreased nonplanarity in the benzo[c]phenanthrene derivatives, but its influence was most pronounced in the benzo[g]chrysene series. A remarkable flattening of the molecule was observed in 9-fluorobenzo[g]chrysene, where the short 2.055 Å interatomic distance between bay-region F-9 and H-8, downfield shift of H-8, and a 26.1 Hz coupling between F-9 and C-8 indicate a possible F-9···H-8 hydrogen bond. In addition, in 9-fluorobenzo[g]chrysene, the stacking distance is short at 3.365 Å and there is an additional interaction between the C-11-H and C-10a of a nearby molecule that is almost perpendicular.
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Affiliation(s)
- Shaibal Banerjee
- Department of Chemistry, The City College of New York, 160
Convent Avenue, New York, New York 10031, United States
| | - Saikat Sinha
- Department of Chemistry, The City College of New York, 160
Convent Avenue, New York, New York 10031, United States
| | - Padmanava Pradhan
- Department of Chemistry, The City College of New York, 160
Convent Avenue, New York, New York 10031, United States
| | - Alessio Caruso
- Department of Chemistry, Vassar College, Poughkeepsie, New
York 12604, United States
| | - Daniel Liebowitz
- Department of Chemistry, Vassar College, Poughkeepsie, New
York 12604, United States
| | - Damon Parrish
- Naval Research Laboratory, Code 6030, 4555 Overlook Avenue,
Washington D.C. 20375, United States
| | - Miriam Rossi
- Department of Chemistry, Vassar College, Poughkeepsie, New
York 12604, United States
| | - Barbara Zajc
- Department of Chemistry, The City College of New York, 160
Convent Avenue, New York, New York 10031, United States
- The Ph.D. Program in Chemistry, The Graduate Center of The
City University of New York, New York, New York 10016, United States
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Kumar R, Singh G, Todaro LJ, Yang L, Zajc B. E- or Z-Selective synthesis of 4-fluorovinyl-1,2,3-triazoles with fluorinated second-generation Julia-Kocienski reagents. Org Biomol Chem 2015; 13:1536-49. [PMID: 25491086 PMCID: PMC4859785 DOI: 10.1039/c4ob02179g] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A highly modular approach to N-substituted 4-(1-fluorovinyl)triazoles is described. In situ desilylation and Cu-catalyzed ligation reaction of TMS-protected α-fluoropropargyl benzothiazole sulfone with aryl, alkyl, and metallocenyl azides furnished second-generation Julia-Kocienski reagents in good to excellent yields. Condensation reactions of these reagents with aldehydes can be tuned to yield E or Z-alkenes selectively. Under mild conditions with DBU as the base, reactions of aldehydes furnished E-alkenes as the major isomer. On the other hand, in condensation reactions with LHMDS as the base and in appropriate solvents, both aldehydes and ketones reacted to yield fluoroalkenes with Z-selectivity. Stereochemical assignment of E/Z olefins obtained in the reaction of a ketone with two Julia reagents was performed via X-ray crystallographic analysis and comparisons of NMR data. The method allows efficient and ready diversification of the N1-substituent and substituents at the double bond.
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Affiliation(s)
- Rakesh Kumar
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, NY 10031
| | - Govindra Singh
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, NY 10031
| | - Louis J. Todaro
- The CUNY X-Ray Facility, Hunter College and The City University of New York, 695 Park Avenue, New York, NY 10065
| | - Lijia Yang
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, NY 10031
| | - Barbara Zajc
- Department of Chemistry, The City College and The City University of New York, 160 Convent Avenue, New York, NY 10031
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