Stereoelectronic Effects in Reaction Design

We have illustrated the diversity and power of stereoelectronic effects in the previous sections. In this section, we provide a general outline of concepts that can be used to implement the stereoelectronic principles in practice in order to design and control chemical reactions and processes. 

Broadly, the applications of stereoelectronics in chemistry can be separated into 

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For the design of organometallic catalytic reactions, one can apply stereoelectronic effects that are specific to the metal centers, such as the trans-effect. An interesting manifestation of this effect in the Rh-catalyzed Claisen rearrangement of propargyl vinyl ethers (Figure 11.13) was found in the computational analysis of this process. ... 

In the first of these sections, we will discuss a broad selection of examples related to organic reaction control, catalyst design, fatty acid mimics, conformations of biopolymers, structure of oligosaccharides that constitute part of the bacteria cell walls, and initiation of enzymaticprocesses associated with sensing hypoxia. Remarkably, each example from this diverse array originates from a common stereoelectronic source, the gauche effect... 

In 1977, Trost published the first example of an asymmetric variant of the Tsuji-Trost reaction, termed the asymmetric allylic alkylation reaction (AAA). Much of the subsequent development of the AAA reaction can be attributed to the dedicated work of Trost and co-workers.There was a substantial time lag however, in the development of processes where high enantioselectivities were realized in a predictable fashion. This was due, in part, to the fact that chiral, asymmetrically pure ligands must create a chiral environment on the opposite face of the allyl fragment to the metal centre (a stereoelectronic requirement, vide infra)P This obviously represents a significant design challenge in the production of effective ligand systems. 

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