A schematic of the solution is shown below. The information from the question is given in black. The types of reactions for each compound are shown in green.
The keys here are (1) being able to draw 1-phenylethanol correctly (2) knowing your reactions and (3) being able to interpret H NMR spectra.
Once the structure of 1-phenylethanol is
drawn, the reactions define
the functional groups of each compound and the locations of the
functional
groups. In many cases, students IGNORED the regioselectivity of the
reactions
and hence failed to confirm structures. Even a quick glance at any of
the
H NMR spectra should have indicated the presence of a monsubstituted
aromatic
group in all the compounds.
With the structures, identified the key
features can be matched to the
H NMR spectra :
| structure |
|
spectra |
|
|
5:1:1:1, vinyl H with complex coupling 5-7ppm |
|
|
|
5:2:3, classic ethyl group coupling pattern |
|
|
|
5:1:3, deshielded 1H quartet and 3H doublet |
|
|
|
5:1 singlet for 1H for acetylenic H |
|
|
|
5:3 singlet for 3H near 2.2 ppm |
|
|
|
5:1 very deshielded H >10ppm for CO2H |
|