Question

Complete the following reaction sequence by drawing in the neutral reagents and products where necessary. The product of this reaction has a molecular formula of C7H6O2 and has a 1H NMR spectrum (CDCl3) of ~12.1 (s), 8.1 (m), and 7.6–7.4 (m) ppm. *Show covalent bonds in all compounds.

Answer 1

Benzoic acid

Step-by-step explanation:

In this case we have a Grignard reaction in which we go from a formula of C6H5Br to C7H6O2. In other words, we add 1 carbon to the molecule. The only way to add one carbon to this molecule is using
`CO_2` as a reagent. When this compound is used as electrophile a carboxylic acid is produced.

Respect to the NMR info, we have a downfield singlet signal at 12.1 ppm which is characteristic of the acid hydrogens in the carboxylic acids (see figure 1). When a carboxylic group is added to the benzene we will obtain the benzoic acid which fits with the formula and the NMR info given.