Hyperconjugation systems without

Different patterns of hyperconjugation (and conjugation) have their own peculiarities neutral hyperconjugation is often more controversial than positive and negative hyperconjugation. In this section, we concentrate on concerted reactions as they are the most difficult type of chanical transformations for the implementation of stereoelectronic control. Because these processes usually avoid the formation of chaiges, the dominant delocalization pattern is neutral, sometimes without a single dominant effect. Furthermore, one has no other choice but to directly analyze the TS in such systems, because concerted reactions avoid the formation of unstable intomediates. 

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