Substitution Reactions Producing Aldehydes and Ketones

SUBSTITUTION REACTIONS PRODUCING ALDEHYDES AND KETONES I. Introduction 

In contrast to previous sections on substitution where hydrogen (Chapter 6), halogen (Chapter 7) or hydroxyl (Chapter 8) attached to carbon was replaced by some other (substituting) species, this section is devoted to the introduction of the carbonyl group where it will be shown to replace a hydrogen. 

This material was already discussed (Chapter 6) and, indeed, reference will be made to that chapter and the more Unaited examples provided there. Here, with the reader somewhat more understanding, it will be recognized that not all of the desired information could have been conveyed earlier. Further, it wUl be seen later 

The observation that an aldehyde group can be substituted for a hydrogen ortho-or para- to a phenolic hydroxyl (an HO- on an aromatic ring) by treatment of the hydroxybenzene (phenol) with trichloromethane (chloroform, CHCI3) in the presence of concentrated aqueous sodium hydroxide (NaOH(aq)) was reported by Reimer and Tiemann in 1876 vide supra and Chem. Ber., 1876, 9, 824). Thus, as shown in Equation 9.67, hydroxybenzene (phenol) undergoes conversion to 

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