Active hydrogen compounds reaction with aryl halides

This method ensures the deposition of very reactive metal nanoparticles that require no activation steps before use. We shall review here the following examples of catalytic reactions that are of interest in line chemical synthesis (a) the hydrogenation of substituted arenes, (b) the selective hydrogenation of a, 3-unsaturated carbonyl compounds, (c) the arylation of alkenes with aryl halides (Heck reaction). The efficiency and selectivity of commercial catalysts and of differently prepared nanosized metal systems will be compared. 

On the other hand, the direct arylation of carbanionic species generated from substrates having relatively acidic hydrogens such as active methylene compounds and ketones can occur (mechanism B) [5,6]. Aryl halides are also capable of coupling directly with appropriately functionalized aromatic substrates and five-membered heteroaromatic compounds as formal carbon nucleophiles via cleavage of their unactivated C-H bonds [5,7-9]. The Fujiwra-Moritani reaction, which is the arylation of alkenes with arenes, is also useful for preparing arylalkenes without employing any halides (mechanism D) [10,11]. 

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