Disconnection, Synthons, Introductory Example

Abstract Retrosynthetic analysis as an imaginative process is introduced. Disconnection and functional group interconversion are discussed. l-(Pyridine-3-yl) propan-l-ol is selected as an exemplary target molecule for retrosynthetic analysis and its (5 -enantiomer for asymmetric synthesis. Interconversions of oxygen functionalities are overviewed. The acidity of the C-H bond as a key property for C-C disconnections is indicated. Some historical and environmental aspects of organic synthesis are concisely presented. 

A proposal for the synthesis of the target molecule, irrespective of its complexity, can be elaborated by retrosynthetic analysis based on the disconnection approach. For chiral molecules this approach results in a proposal for the synthesis of racemic target molecules. Preparation of one enantiomer, or optically pure target molecule, enables asymmetric synthesis. 1-(Pyridine-3-yl)propan-l-ol is selected to demonstrate various retrosynthetic approaches to this relatively simple target molecule and to show the complexity of asymmetric syntheses of the preferred enantiomer. An introductory example is elaborated in some detail to familiarize the reader with the philosophy behind retrosynthetic analysis and to underline the need for chiral information in the reacting system to complete asymmetric synthesis. Today chiral variants of synthetic reactions are the subject of intensive research, and it is said that their number is limited only by the creativity of the organic chemist. 

To demonstrate the progress of organic synthesis, some historical signposts are presented and the environmental aspect of industrial syntheses briefly discussed. 

Sunjic and V. Petrovic Perokovid, Organic Chemistry from Retrosynthesis 

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