The Wittig reaction in the undergraduate organic laboratory

Warner, John C.; Anastas, Paul T.; Anselme, J.‐P.

doi:10.1021/ed062p346

Cited by 14 publications

(24 citation statements)

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“…A host of phosphonium salts is available which provides a massive diversity of alkene products. These reactions can be performed on large or small scale, are often high yielding, and can easily be performed by student chemists . The Wittig reaction was awarded a Nobel Prize in Chemistry .…”

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confidence: 99%

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Synthesizing Stilbene by Olefin Metathesis Reaction Using Guided Inquiry To Compare and Contrast Wittig and Metathesis Methodologies

et al. 2018

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In this experiment, students are asked to conduct a catalytic cross-metathesis experiment and compare this reaction to the Wittig reaction within the confines of green chemistry. Students synthesize stilbene from styrene using Grubbs second-generation catalyst. Products can be minimally characterized by IR spectroscopy and melting point, but using 1 H NMR spectroscopy is preferred. Students find that the Wittig reaction is selective for cis-stilbene while the metathesis reaction produces >98% trans-stilbene. Students determine the cis/trans selectivity, turnover number, and maximum turnover frequency of the reaction. The experiment is conducted alongside the synthesis of stilbene using Wittig chemistry from a published procedure.

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confidence: 99%

“…In an Advanced Organic Laboratory course, students were asked in two consecutive laboratory experiments to synthesize stilbene. In the first experiment, students use Wittig chemistry from a previously published experiment . In the second experiment, stilbene is synthesized by the cross-metathesis of styrene.…”

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confidence: 99%

Synthesizing Stilbene by Olefin Metathesis Reaction Using Guided Inquiry To Compare and Contrast Wittig and Metathesis Methodologies

et al. 2018

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“…In 1973, Markl and Merz reported the simultaneous preparation of cis - and trans -stilbenes from the Wittig condensation of benzaldehyde with benzyltriphenylphosphonium chloride (Scheme ). This method was eminently applicable to undergraduate teaching laboratories and has been widely adopted in this context globally …”

Section: Introductionmentioning

confidence: 99%

“…This method was eminently applicable to undergraduate teaching laboratories and has been widely adopted in this context globally. 3 In principle, it is possible to separate the cis-and transstilbene regioisomers for their analytical characterization using techniques such as melting point, FTIR spectroscopy, or electronic absorption spectrophotometry. However, high-field 1 H NMR spectroscopy removes the requirement for prior purification of the products arising, since the relative yields of the cis-and trans-regioisomers can be determined simply by integrating the alkene signals located at 6.63 and 7.13 ppm, respectively, with triphenylphospine oxide not appearing in this part of the NMR spectrum.…”

Section: ■ Introductionmentioning

confidence: 99%

“…This method was eminently applicable to undergraduate teaching laboratories and has been widely adopted in this context globally. 3 broken (Figure 1). Therefore, this represents one of the most compelling reasons for inclusion of benchtop NMR spectrometers within undergraduate laboratories, in order to allow students to have a 'hands-on', real-time access to a means of analysis which provides substantial information on their analyte samples during laboratory classes.…”

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Benchtop NMR Spectroscopy and Spectral Analysis of the cis- and trans-Stilbene Products of the Wittig Reaction

et al. 2019

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Benchtop NMR spectrometers are now becoming more widely employed in university teaching laboratories. These low-field instruments are increasingly used in reaction monitoring and product purity applications. NMR spectra obtained using these spectrometers (40-80 MHz) tend to suffer from significant overlap of signals when compared to those obtained at 300-400 MHz or above, and therefore some reactions may be less suited to analysis using such benchtop systems. Whilst some 15 reactions can be modified to make them more amenable to analysis on low-field benchtop spectrometers, the fact remains that many common undergraduate laboratory chemistry reactions remain as a stalwart of the university education system. Therefore, there is currently a major requirement for benchtop NMR analysis to improve in order to facilitate student understanding.Herein, it is demonstrated a combination of spectral analysis and simulation at low-fields (40-80 20 MHz) that allows the fine structure of second-order effects and overlapping spectra to be deduced, enabling an improved understanding of the low-field benchtop NMR technique within undergraduate student cohorts. The evolution of well-resolved and distinct multiplets at 400 MHz to complex, overlapping multiplets at 40-80 MHz also serves as a useful guide for laboratory demonstrators and academic staff when explaining the advantages of such benchtop systems. The 25 Wittig reaction has been a standard reaction practical session in many university teaching laboratories since the 1980s, the products of which are a mixture of cis-and trans-stilbenes. This reaction serves as an ideal example of how benchtop NMR and analysis can support chemistry teaching laboratories.

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