Grignard reaction: alkylation with cadmium chloride

Grignard reagents derived from aryl bromides are readily prepared and may be converted into organocadmium compounds by treatment with cadmium chloride (cf. Section 5.8.4, p. 616). Reaction of an organocadmium with a carboxylic acid chloride constitutes a convenient synthesis of aryl alkyl ketones. 

The use of organocadmium compounds, RjCd, lies in the fact that they react only with acid chlorides and no other carbonyl compounds. Thus, acid chlorides can be converted to ketones with no risk of further reaction. Organocadmium compounds are prepared (Equation 15.3) by reaction of cadmium chloride with a Grignard reagent, and the reactions only work well when R is aryl or primary alkyl. An example is provided in Figure 15.45. 

---