Strategy VIII Introduction to Carbonyl Condensations

The next 10 chapters are about the synthesis of carbon skeletons with two functional groups. Compounds such as 1-3 will all be treated as 1,3-difunctionalised compounds since the important thing is not the type of functional group but the relationship between them. Our logic is that all FGs can be derived from alcohols, ketones (or aldehydes) or acids by substitution and that those three can be interconverted by oxidation or reduction. 

The corresponding disconnection is of the newly formed C-C bond 8a. The synthons are the acyl cation and a nucleophilic carbon species that might be a metal derivative RM (chapter 13) but will generally be an enolate in the next 10 chapters. And that is how carbonyl compounds are nucleophilic. 

Organic Synthesis The Disconnection Approach. Second Edition Stuart Warren and Paul Wyatt 2008 John Wiley Sons, Ltd 

Carbonyl compounds such as acetone 10 exist predominantly in the keto form 10 but are in equilibrium with the enol form 11. We shall be more interested in the formation of the enolate anion 13 with base 12 and its reactions at the a-carbon with carbon electrophiles. 

The disconnection is of the newly formed C-C bond 14a and is not the same as 8a. The synthons are represented by the enolate anion and a carbon electrophile. We saw alkyl halides in this role in chapter 13 but in the next 10 chapters we shall be mostly interested in combining enol(ate)s with carbonyl compounds. 

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