1. When monitoring the reaction by TLC you see that the most benzaldehyde starting material has an Rf of 0.25. What should you do?
| a. Use a greater amount of Ethyl Acetate in relation to the amount of Hexane until the Rf is 0.5 |
| b. Use a greater amount of Hexane in relation to the amount of Ethyl Acetate until the Rf is 0.5 |
| c. Rf value of 0.25 is fine as the product of this reactions the product will be more non-polar than the starting material and will travel further up the TLC plate |
| d. Let the TLC run longer |
The NMR data giving for the product is as follows:
d 7.05 (s, 5 H), 5.95â5.30 (m, 1 H), 5.19â4.80 (m, 2 H), 4.60 (t, J = 6 Hz, 1 H), 2.44 (t, J = 6 Hz, 2 H), 2.06 (br s, 1 H).
What proton is represented at "2.06 (br s, 1 H)"?
| a. Proton connected to oxygen |
| b. Internal proton of the alkene |
| c. The proton that is on the carbon alpha to the alcohol |
| d. This is the impurity of water in DMSO |
What solvent do the authors run their NMR in?
The NMR data giving for the product is as follows:
d 7.05 (s, 5 H), 5.95â5.30 (m, 1 H), 5.19â4.80 (m, 2 H), 4.60 (t, J = 6 Hz, 1 H), 2.44 (t, J = 6 Hz, 2 H), 2.06 (br s, 1 H).
If you ran the NMR in d-DMSO and see an additional peak at 1.76ppm and 3.60ppm, what do these peaks represent.
| a. Residue THF impurity, as THF was used as a solvent in the reaction |
| b. Allyl Bromide Statring Material |
| c. Benzaldehyde Statring Material |
| d. water impurity as water was used as a solvent in the reaction |
| e. These resonances representatives the protons of ammonium chloride which was used in the reaction |
This paper states this addition of an allyl halide to a aldehyde is a "Grignard-Like" reaction. Although, traditionally reactions using allyl halides and zinc to perform carbon-carbon bond formation are known as the Barbier Reaction