Substitution at sp2 center

(i) Transition metal-catalyzed cross-coupling reactions 

Transition metal-catalyzed cross-coupling reaction has become the most important method for the formation of aryl-aryl bonds. The reaction of aryl halides and sulfonates with organomagnesium compounds is usually referred 

Bromo- and iodoanilines, -phenols and -benzoic acids, after in situ deprotonation by the excess of the reagent, can be coupled (PdCl2(dppf), 1 mol%, THF, RT, 3h) with organomagnesium halides, thus avoiding protection-deprotection steps.1 

(b) Substituted alkenes as electrophiles in cross-coupling reactions 

Chiral a-carbamoyloxy-2-alkenylboronates react with Grignard reagents with complete a- and diastereoselectivity through rearrangement of an intermediate ate -complex, yielding chiral allylboronates, which were oxidized to 

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