Radical Formylation and Hydroxymethylation with CO

In a useful application, Kahne and Gupta reported the radical hydroxymethyla-tion (formylation and in situ reduction) of organic halides, including sugar derivatives, using a catalytic amount of triphenylgermyl hydride in the presence of so- 

4 Modern Free Radical Methods for the Synthesis of Carbonyl Compounds 

The reducing ability of one-electron reducing reagents, such as zinc, can be used in the radical formylation of alkyl iodides, where one-electron reduction and proton quenching constitute the final step in the production of aldehydes [19]. Unfortunately, this zinc method involves competing reactions and a narrow scope in terms of substrates. 

Unlike tin radicals, thiyl radicals cannot abstract halogens from organic halides because of a mismatch in the polar effect but can add to C-C double and triple 

The combination of alkanes and CO is the simplest of all carbonylation methods which lead to aldehydes. Three research groups have reported the conversion of cyclohexane and carbon monoxide to cyclohexanecarboxaldehyde based on radical carbonylation by photolysis [26]. This alkane-formylation by radical carbo-nylations is conceptually important, but needs further improvement in order to be a useful synthetic method. 

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