Grignard reagents reaction with formic acid

Reaction with formic acid. The.reaction of Grignard reagents with formic acid was originally (1905) reported to give aldehydes in low yield and has seen little use. Actually, the reaction proceeds in fair yields even in ether and in higher yields in THE. Aldehydes can also be prepared by the method outlined in equation (I).3... 

Reduction of carboxylic acids to aldehydes Replacement of the Rosenmund reaction (conversion of carboxylic acids to acid chlorides followed by catalytic hydrogenation) or the reaction of Grignard reagents with formic esters by molecular hydrogen and heterogeneous catalysts (Ru3Sn7 alloy). 

The reaction of Grignard reagents with formic acid has been reinvestigated. Yields of aldehydes are improved if THF is used as solvent [equation (4)], A study of orthoformates in Grignard reactions indicates that yields of aldehyde acetals are considerably higher when the 2-alkoxy-l,3-dioxolan (7) is used in place of triethyl orthoformate. ... 

Note that derivatives of formic acid, HCO2H, will be converted into secondary alcohols by this double reaction with a Grignard reagent. 

The methyl ester has also been obtained by esterification of cyclopentanecarboxylic acid.8 The acid, in turn, has been prepared by the Favorskii rearrangement,6 7 9-11 by the reaction of cyclopentyl Grignard reagent with carbon dioxide,12 by the carbonylation of cyclopentyl alcohol with nickel carbonyl13 or with formic acid in the presence of sulfuric acid,14 and by the hydrogenation of cyclopentene-1-carboxylic acid prepared from ethyl cyclopentanone-2-carboxylate 15 or from cyclopentanone cyanohydrin.16... 

Acetic formic anhydride has been prepared by the reaction of formic acid with acetic anhydride2 3 and ketene,4,5 and of acetyl chloride with sodium formate.6 The present procedure is essentially that of Muramatsu.6 It is simpler than others previously described and gives better yields. It is easily adapted to the preparation of large quantities, usually with an increase in yield. Acetic formic anhydride is a useful intermediate for the formyl-ation of amines,3,7 amino acids,8,9 and alcohols,2,10 for the synthesis of aldehydes from Grignard reagents,11 and for the preparation of formyl fluoride.12... 

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