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

Mark Edgar, Benita C. Percival, Miles Gibson, Jinit Masania, Ken Beresford, Philippe B. Wilson and Martin Grootveld, Journal of Chemical Education, (2019) DOI: 10.1021/acs.jchemed.8b00657

It is demonstrated that a combination of spectral analysis and simulation at low-fields (40–80 MHz) 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 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 spectrometers and analysis can support chemistry teaching laboratories.