Consider the following reaction: Which of the following reagents can be used as R to successfully carry out this transformation? I. CH ₃ CH ₂ MgBr II. CH ₃ CH ₂ Li III. ( CH ₃ CH ₂)₂ Cd IV. ( CH ₃ CH ₂)₂ CuLi

Step-by-step solution

The given transformation involves the conversion of an acid chloride ( p -nitrobenzoyl chloride) to a ketone ( p -nitropropiophenone). Grignard reagents (like CH ₃ CH ₂ MgBr ) and organolithium reagents (like CH ₃ CH ₂ Li ) are highly reactive nucleophiles. They react with acid chlorides to initially form ketones, but they rapidly react further with the resulting ketones to yield tertiary alcohols. Thus, reagents I and II cannot be used to stop the reaction at the ketone stage. On the other hand, dialkylcadmium rea