Lateral lithiation mechanism

Here is an example 168 of a reaction in which both benzyne formation and lateral lithiation are involved. What s going on here Try to work out the mechanism before reading the explanation. You have the clues you need - the reaction involves the formation of a benzyne and a lateral lithiation.31... 

We have tried to summarize in this chapter the basic tendencies and mechanisms of directed metalation. DoM in presence of DMG(s) allows for the regioexhaustive functionalization of aromatics. DreM, frequently combined with migration of the DMG or rearrangement, gives a powerful tool for the synthesis of natural products. Peri and lateral lithiations have shown to further enable functionalization for aromatic scaffolds, and last but not least, when coordinated to and thus activated by a metal complex, aromatic ring systems can be subjected to enantiose-lective metalation reactions. Although such a chapter cannot cover the topic in an exhaustive manner, we hope to have found a compromise between scholarly presentation and citation of relevant literature. 

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