A Green, Guided-Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory

Eby, Eric; Deal, S. Todd

doi:10.1021/ed085p1426

Cited by 21 publications

(15 citation statements)

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“…GI approaches, based on the theory of constructivism, engage students through encouraging the use of critical thinking skills, the application of foundational knowledge, and concept discovery through the analysis of data with limited facilitation from faculty. − GI activities and experiments have been shown to be an effective teaching pedagogy in the chemical sciences, − and many examples of laboratory and classroom activities for introductory, ,,, organic, ,− and analytical − chemistry have been reported.…”

Section: Conversion To An Online Formatmentioning

confidence: 99%

Transitioning an Upper-Level, Integrated Laboratory Course to Remote and Online Instruction During the COVID-19 Pandemic

Villanueva

Zimmermann

2020

J. Chem. Educ.

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While the suspension of face-to-face instruction disrupted laboratory components of most chemistry-based classes at the college level, it was notably disruptive to upper-level chemistry courses based solely on laboratory experiences. This communication describes the logistical and pedagogical efforts made in an integrated, upper-level, laboratory-based chemistry course at Georgia Gwinnett College to engage students and to develop a relevant and meaningful assignment during the COVID-19 suspension of face-to-face classes. Instructor descriptions and reflections, examples of assignments, student feedback, and revisions for future iterations of this course are presented within.

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Section: Conversion To An Online Formatmentioning

confidence: 99%

Transitioning an Upper-Level, Integrated Laboratory Course to Remote and Online Instruction During the COVID-19 Pandemic

Villanueva

Zimmermann

2020

J. Chem. Educ.

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“…Two sections of students (21) were completing a full year of organic chemistry, whereas one section of students (12) had not taken organic chemistry at this time. Each student was provided information on Sanger's reagent and its use for derivatizing amino acids.…”

Section: Applications To Nucleophilic Aromatic Substitution Reactionsmentioning

confidence: 99%

Electrostatic Potential Maps and Natural Bond Orbital Analysis: Visualization and Conceptualization of Reactivity in Sanger’s Reagent

et al. 2015

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Frederick Sanger's early work on protein sequencing through the use of colorimetric labeling combined with liquid chromatography involves an important nucleophilic aromatic substitution (S N Ar) reaction in which the N-terminus of a protein is tagged with Sanger's reagent. Understanding the inherent differences between this S N Ar reaction and other nucleophilic substitution reactions (S N 1 and S N 2) can be challenging for students learning organic chemistry. Here, both electrostatic potential (ESP) maps and natural bond orbital (NBO) analyses are employed to visualize and conceptualize Sanger's key observation of the difference in reactivity between 2,4-dinitrochlorobenzene and 2,4-dinitrofluorobenzene. The utility of this method is extended to compare the reactivity of a series of halobenzenes for S N Ar fluorination, a widely used reaction in pharmaceutical and medicinal fields. In combination with experimental results from the literature, the ESP maps and NBO analyses are consistent with and provide excellent corroboration with the reactivity of different substrates toward S N Ar reactions.

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“…Finally, two more alcohols were identified that undergo the desired reaction, importantly, under identical conditions, in these cases via a tertiary carbocation. Figure 5 (top) shows the reactions of 1,4-dimethoxybenzene with 3-methyl-3-pentanol (5′) to form 1,4-bis(1-ethyl-1-methylpropyl)-2,5-dimethoxybenzene (5) and Figure 5 (bottom) shows the reaction with 3ethyl-3-pentanol (6′) to form 1,4-bis(1,1-diethylpropyl)-2,5dimethoxybenzene (6).…”

Section: Enhancing the Discovery Aspect Of The Laboratorymentioning

confidence: 99%

“…Not all of the molecular masses are unique, so students may also rely on the fragmentation patterns to support their structural assignments. Analysis of these molecular ions and fragmentation patterns indicates loss of a methyl (1, 4, 5), ethyl (2,6), or isopropyl group (3), depending on the structure of the product. A representative set of mass spectra may be found in the Supporting Information.…”

Section: Mass Spectrometrymentioning

confidence: 99%

Expanding the Scope of an Electrophilic Aromatic Substitution Discovery Experiment Including Hydride and Methyl Shifts

et al. 2021

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Friedel–Crafts alkylation reactions using a curated set of alcohols provide students with the opportunity to combine the study of electrophilic aromatic substitution with carbocation rearrangements. In this experiment students may be presented with up to nine alcohols that yield six products, all synthesized under identical reaction conditions. They distinguish their products using a range of instrumental methods including infrared, 1H NMR, and 13C NMR spectroscopies, and mass spectrometry. Additional characterization is provided by the determination of melting point/mixed-melting point and gas chromatographic retention time. Students work in teams to assign structures to their individual reaction products; providing nine starting materials ensures minimal duplicates in a given laboratory section. As students interpret their data, some discover that a carbocation rearrangement occurred, resulting in isolation of only one product despite starting from a pair of isomeric reagents. This laboratory provides students with the opportunity to engage in a range of laboratory and problem-solving skills, and thus is designed to be performed toward the end of a two-semester organic chemistry sequence.

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A Green, Guided-Inquiry Based Electrophilic Aromatic Substitution for the Organic Chemistry Laboratory

Cited by 21 publications

References 0 publications

Transitioning an Upper-Level, Integrated Laboratory Course to Remote and Online Instruction During the COVID-19 Pandemic

Transitioning an Upper-Level, Integrated Laboratory Course to Remote and Online Instruction During the COVID-19 Pandemic

Electrostatic Potential Maps and Natural Bond Orbital Analysis: Visualization and Conceptualization of Reactivity in Sanger’s Reagent

Expanding the Scope of an Electrophilic Aromatic Substitution Discovery Experiment Including Hydride and Methyl Shifts

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