Biaryl experimental procedures

Other sources for cross-coupling reactions are aldehydes and carboxylic acids after decarbonylation and decarboxylation, respectively, which can be reacted with aryl halides to form biaryls. The following Experimental Procedure illustrates the potential of this quite atom-economic reaction. In this case, a copper co-catalyst promotes both the decarboxylation and the cross-coupling. 

Symmetrical biaryls can be prepared from the corresponding aryl bromides and hexamethylditin or bis(pinacolato)diboron (Experimental Procedure below). 

In their first attempts, they applied the original protocol published by Miyaura and associates using K2CO3 as the base on several haloarenes and were pleased to obtain the corresponding biaryls in good to excellent yields (Experimental Procedure below). Recently, MacMillan and co-workers used a similar protocol for the intramolecular biaryl coupling targeting the natural product diazonamide. ... 

The transformation from arenes into phenol acetates can be achieved with hypervalent iodine compounds (such as phenyliodonium acetate, PhI(OAc)2), with chromates, or under aerobic conditions. Ligands, like picolinic acids, stabilize the intermediate palladium(IV) salts. In the presence of Lewis acids or silver salts, biaryl formation takes place. The influence of different directing groups has recently been reviewed. For example, diaryl sulfones or sulfoxides having at least one heteroaryl attached can be oxidized to the corresponding aryl acetates (Scheme 5-194, Experimental Procedure below). ... 

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