Amine From aryl halide

Direct Pd-catalyzed C-N and C-O bond formation from aryl halides and amines in the presence of stoichiometric amount of base. 

A three-component reaction based on the umpolung of re-allylpalladium (II) complexes indium metal was reported by Grigg and co-workers (Scheme 8.31) [74]. In this reaction, the electrophilic nature of the n-allyl palladium species generated from aryl halides and allenes is reversed by transmetallation with indium metal. The resultant nucleophilic allylindium reagent subsequently adds to the third component - aldehyde [75] or imine [76] - to give the corresponding homo-allylic alcohol 64 or amine 65 respectively. 

A general mechanism for the palladium-catalyzed amination of aryl halides is presented in Scheme 7. This picture has been developed from studies performed largely upon isolated complexes, with the oxidative addition and reductive elimination steps being investigated in the greatest detail. On... 

A-Arylindoles and A-arylimidazoles were prepared from aryl halide using a copper catalyst. Diarylzinc reagents react with A-(OBz) amine derivatives, with a copper catalyst, to give the A-aryl amine. " ... 

The overall mechanism for palladium-catalyzed amination of aryl halides is shown in Scheme 4. Initially, a palladium(O) complex is rapidly formed from Pd(OAc)2 and phosphine ligand in the presence of amine and base. If Pd(dba)2 is used, then either bisphosphine Pd(0) complexes are formed, as with P(Bu-f)3170, or mixed phosphine/dba palladium(O) complexes are formed as with arylphosphines171. When the reactions are initiated with dba complexes, dba is consumed under the reaction conditions, and simple bis-ligand Pd(0) complexes are formed. The mechanism for reduction of Pd(II) to Pd(0) has been studied172, but the process occurs more rapidly in the presence of amine and base than in the absence of these reagents, even when the amine cannot undergo /3 -hydrogen elimination. 

DMF is recommended as diluent in the Ullmann synthesis of diaryls from aryl halides and as solvent for the Beckmann rearrangement of steroidal enone oximes. The Willgerodt-Kindler reaction (a carbonyl compound with a secondary amine and sulfur to give a thioamide) can be carried out in good yield at 50-60 if DMF is... 

During (he last few years, a novel Pd(O)-catalyzed method for C-N bond formation from amines and aryl halides has emerged largely due to contributions from the Buchwald and Hartwig groups [120, 121]. In one application, an intramolecular C-N bond linkage was realized using classic palladium catalysis condition in Buchwald s synthesis of tetrahydropyrroloquinoline... 

Cross-coupling reactions leading to the formation of C-X (X = heteroatom) bonds catalyzed by Pd(dba)2 have been reported. Aniline derivatives have been prepared via reaction of amine nucleophiles with aryl halides in the presence of Pd(dba)2 and phosphines, especially P( Bu)3. Likewise, diaryl and aryl alkyl ethers are produced from aryl halides (Cl, Br, I) and sodium aryloxides and alkoxides under similar conditions. Conditions effective for the coupling of aryl chlorides with amines, boronic acids, and ketone enolates using an easily prepared phosphine chloride as a ligand have recently been uncovered (eq 22). The preparation of aryl siloxanes and allyl boronates via Pd(dba)2-catalyzed C-Si and C-B coupling have been reported as well. 

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