Disconnection with Participation of Two Functional Groups

Until now, we have considered the disconnection of C-C bonds by participation of one functional group. In this chapter, we discuss examples where two functional groups control selection of the preferred C-C bond for disconnection by their electronic effects. Most heteroatoms (O, N S, Hal) in organic molecules are more electronegative, whereas P, Si and aU metals are more electropositive than carbon. The polarization C-heteroatom bond dictates the direction of the imaginative flow of the electrons in the disconnected C-C bond at a distance from the functional group. 

For the following discussion it is important to recall that any functional group in organic molecules rises the charge separation along the carbon chain. The through-bond distance of two functional groups in bifunctional molecules defines 

Sunjic and V. Petrovic Perokovic, Organic Chemistry from Retrosynthesis to Asymmetric Synthesis, DOI 10.1007/978-3-319-29926-6 4 

In the next chapter, specific issues with illogical disconnections of target molecules with an even number of atoms separating two oxygen functionalities are addressed. 

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In this and the next chapter we consider disconnection with participation of two oxygen functionalities, called the dioxygenated pattern. The rationale behind this selection rests in the fact that oxygen functionalities can be conveniently transformed into functional groups with other heteroatoms. Schematic stmctures of the 1,3-dioxygenated pattern are presented as TM I-III (Fig. 4.3). 

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