Experiment 21 - Experiment 21 Discussion NMR The H NMR of the starting aldehyde has 5 unique signals The most deshielded corresponds to the

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Experiment 21 Discussion NMR: The H NMR of the starting aldehyde has 5 unique signals. The most deshielded corresponds to the aldehyde hydrogen. The signals are then determined through proximity to the functional groups in the following order: meta to the aldehyde group nearest the nitro group, ortho to aldehyde, meta furthest from the nitro group, and finally the H in the para position. The C NMR of the aldehyde has 7 signals. The most deshielded is the carbonyl carbon. In order from most to least deshielded the carbons are: ortho with nitro substituent, benzene carbon with aldehyde substituent, saturated ortho carbon, meta carbon closest to aldehyde group, para carbon, and finally meta carbon closest the nitro group. The H NMR of the ylide has 5 signals. From most to least deshielded it is: The 3 signals that correspond to benzene hydrogens, the alkene hydrogen, and the hydrogens on the methyl ester group. The C NMR from most to least deshielded is: the carbonyl carbon, the 4 benzene carbons, the methyl carbon attached to oxygen, and the unsaturated alkene carbon. The signal just under 80ppm is solvent. Phosphorous coupling is evident at the signal just below 130 ppm and at 30 ppm, corresponding with the benzene and alkene Cs attached to P. They can be distinguished by the two symmetrical peaks that happen because of P isotopes. The C NMR of the alkene product from most to least deshielded are
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This note was uploaded on 02/21/2011 for the course CHEM 3b taught by Professor Pederson during the Fall '08 term at University of California, Berkeley.

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Experiment 21 - Experiment 21 Discussion NMR The H NMR of the starting aldehyde has 5 unique signals The most deshielded corresponds to the

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