Modified Ullmann

N-Arylation of azoles is achieved either by using arynes, activated halobenzenes (e.g. dinitro) or under Ullmann conditions. Thus benzyne reacts with imidazoles to give N-arylimidazoles (70AHC(12)103), and these compounds have also been prepared under modified Ullmann conditions. 

The coupling of the aryl aldehyde 84 and the a-iodoenone 85 was effected by a modified Ullmann reaction (83 %, Scheme 3.16) [42], The resulting arylation... 

Modified Ullmann biaryl ether / thioether and biaryl amine synthesis ... 

In the laboratory of K.C. Nicolaou, a novel mild method for the preparation of biaryl ethers was developed. The di-ort/70-halogenated aromatic triazenes underwent efficient coupling with phenols in the presence of CuBr. This mild modified Ullmann condensation was utilized in the synthesis of the DOE and COD model ring systems of vancomycin. 

The Ziegler-modified Ullmann reaction was used for the total synthesis of pyrrolophenanthridinium alkaloid tortuosine by L.A. Flippin and co-workers. First, A/-Boc-5-methoxyindoline was lithiated at C7 with s-BuLi in the presence of TMEDA, and then it was transmetallated to the corresponding organocopper species that smoothly underwent the Ullmann reaction with a 3-iodoaryl imine. The resulting biaryl product was treated with anhydrous HCI in chloroform, which promoted the cyclization followed by dehydration to give the natural product. 

Cuprous oxide was found superior to other copper species as reagent and catalyst for (he preparation of diaryl ethers by a modified Ullmann condensation, ... 

With the correct substitution pattern about the pyridine ring established, we wished to introduce the methoxy group at the 5-position. While the 4-methoxy substituent was smoothly introduced by nucleophilic aromatic substitution, this proved unsuccessful at the 5-position. However, a modified Ullmann coupling procedure that... 

This modified Ullmann reaction was used to synthesize the antileukemic agent ( )-steganacin (I), as outlined in equation (11). ... 

Polymers with di(carbazol-3-yl)phenylamine and A,A -di(carbazol-3-yl)-iV,iV -diphenyl-l,4-phenylenediamine units in the main chain can be synthesized by a modified Ullmann condensation. The mechanism is shown schematically in Figure 1.4. The glass transition temperatures range from 102 to 216 °C. 

Hyperbranched PPEs with phenolic terminal groups can be prepared from 4-bromo-4, 4"-dihydroxytriphenylmethane via a modified Ullmann reaction. The monomer is treated with potassium carbonate or sodium hydroxide as a base. Copper chloride is used as a catalyst in an aprotic solvent, namely, dimethyl sulfoxide or sulfolane. The degrees of branching reach from 48-71%. The phenoUc end groups can be easily modified. 

Methylene-2-azetidinones from p-bromo-p,Y-ethylenecarboxylic acid amides Modified Ullmann-Goldberg reaction... 

DoM-Ullmann Cross-Coupling. Synthesis ofAr-X-Ar (X = 0, N, S) under Modified Ullmann Reaction Conditions (General Procedure, Table 14.19)... 

The Modified Ullmann Reaction (Ullmann-Condensation-Type Arylations)... 

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