Ketone syntheses by means of organometallic compounds

Interaction of carbonyl halides and Grignard reagents normally leads to tertiary alcohols, but it stops at the ketone stage if formation of this alcohol is hindered by, e.g., steric hindrance  

Yields are appreciably better if the Grignard reagent is first converted in an organozinc compound zinc chloride in ether is dropped into the Grignard solution at a rate sufficing to keep the solution at the boiling point  

The resulting organozinc chloride is then treated with the acid chloride, giving up to 93% yields of ketone.357 For ketone syntheses by means of ethylzinc iodide see Morton, Davidson, and Newey.311 

Klein and Neff358 prepared mono- and di-ketones as well as oxo esters in excellent yield by treating alkylzinc iodides with carbonyl chlorides, dicarbonyl dichlorides, or monoester monochlorides of dicarboxylic acids. The alkylzinc iodides were obtained directly from the alkyl iodides and a zinc-copper alloy in toluene-ethyl acetate, as in the following example. 

Cadmium alkyls, obtainable from Grignard reagents and cadmium chloride,329 also lead to ketones when treated with acid chlorides  

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