Dichloro-2- 2-thienoyl benzoic acid

Similar considerations apply to reactions of organomagnesium compounds with formate esters (leading to aldehydes), chloroformates or carbonates (leading to esters) or carbamoyl chlorides (leading to amides)  

For the synthesis of aldehydes, reactions with formamides are preferable (see Section 6.3), though modest yields have been reported in a few cases [A], The other reactions can give good yields [A], as in the following procedure, but have been little exploited. 

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