Interconversions of Oxygenated Functional Groups

Alcohols are frequent sources of organic compounds with other heteroatoms, and their interconversion is the subject of many retrosynthetic FGIs. Interconversion of various functional groups to primary or secondary alcohols is another frequent retrosynthetic step, since alcohols can be disconnected to available building blocks (Sect. 2.1). 

Transformation of carboxylic acids into more reactive derivatives, particularly halides and anhydrides, is an activation of the carboxylic group. Formation of more reactive carboxylic acid derivatives may be described as moving the carboxylic group energetically uphill, from where it can be favorably transformed downhill into a less reactive congener. Activated carboxylic acid derivatives characterize the localized partial positive charge on the carbonyl C atom and reactivity against weak nucleophiles such as water, alcohols, ammonia or amines. 

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