Consider the following compound. The compound reacts with SOCl ₂ to produce P. P reacts with dimethyl cadmium to produce Q. Q upon reaction with ethyl magnesium bromide (3 equiv) followed by water workup produces R. The structure of R is:

Step-by-step solution

The starting compound is CH₃O-CO-CH₂-CH₂-CH₂-COOH , which contains both a methyl ester and a carboxylic acid group. Reaction with SOCl₂ selectively converts the carboxylic acid group ( -COOH ) into an acid chloride group ( -COCl ). The ester group remains unaffected. Compound P is CH₃O-CO-CH₂-CH₂-CH₂-COCl . Dimethyl cadmium ( (CH₃)₂Cd ) is a mild organometallic reagent that specifically reacts with acid chlorides to form ketones, but it does not react with esters. It replaces the -Cl with a -CH₃ group. Compound Q i