Arylation Ullman type

Ullman type coupling occurs between aryl halides and trifluoromethyl copper species generated by the action of copper iodide on sodium tnfluoroacetate [168, 169] or on methyl fluorosulfonyldifluoroacetate [170] (equation 145) Similarly the pentafluoroethyl group can be introduced from potassium pentafluoropropion-ate [171] (equation 146)... 

The copper-catalysed, Ullman-type coupling of aryl, heteroaryl and alkenyl halides may be achieved at ambient temperature using copper(I) thiophene-2-carboxylate as catalyst.60 A new semiconducting poly(anthraquinone-l,5-diyl) with nitro groups at the 4- and 8-positions has been prepared by Ullman-type coupling using metallic copper or a zerovalent nickel complex as catalyst.61... 

A Cu-catalyzed, Ullman-type intramolecular arylation of a protected amine afforded l,5-benzodiazepin-2-ones in good yield via a type a ring closure (Scheme 66) <20050L4781>. An 1V-BOC or IV-diisopropylphosphono (DIPP) protecting group was essential for the success of this reaction since unprotected amines failed to cyclize under the same conditions. 

A formally related yet most likely Ullman type of arylation of nitrogen nucleophiles was reported most recently. A bimetallic catalytic system of Fe(acac)3—CuO was shown to be highly active in the simple arylation of a variety of N-heterocycles with aryl iodides and bromides in the presence of CsC03. Although a deeper mechanistic understanding awaits further investigations, the broad scope plus its operational simplicity make this procedure especially amenable to applications on an industrial scale (Scheme 7.6) [10]. 

The Ullman-type coupling of 3-pyridylcopper with aryl iodides has been reported yields are improved when the arylcopper is stabilized by the addition of an equivalent of triphenylphosphine (equation 53)75. 

Although activated aryl halides can A-arylate imidazole anions, less reactive reagents require the extreme conditions of Ullman-type processes (see CHEC-I). With the more reactive aryl halides (e.g.,... 

In Ullman-type coupling, aryl boronic acids are much more efficient coupling partners with amines and phenols as compared with aryl halides. They successfully couple at room temperature in the presence of a copper acetate/triethylamine (or pyridine) catalyst system and the corresponding arylated products were provided in high yields (Scheme 15.20). Similarly, aryl boronic acids are successfully coupled with structurally and electronically diverse substrates such as amides and sulfonamides to afford the corresponding IV-arylated products. 

Direct coupling of vinyl halides and phenols under Ullman-type reaction conditions can be useful for the preparation of aryl vinyl ethers, and intramolecular version of this process has been applied to the synthesis of spirocyclic oxindoles through a sequence of intramolecular Ullman coupling and Claisen rearrangement reactions (eq 58). ... 

As a metal-mediated approach, intramolecular Ullman-type reaction of 2-(2-haloaryl)phenols with copper salts has been used for dibenzofuran synthesis [35]. However, harsh reaction conditions are generally required. On the other hand, Liu et al. developed the copper-mediated intramolecular O-arylation of 2-(2-haloaryl)phenols under milder and neutral conditions [36]. The reaction of 2-(2-chloroaryl)phenols 65 with electron-withdrawing substituent(s) gave the corresponding dibenzofurans 66 in high yields (Scheme 23.25). They also demonstrated the... 

Organocopper intermediates are involved in another broad class of reactions which accomplish the coupling of two organic substrates. The classical example of this type of reaction is the Ullman coupling of aryl halides, which is usually done with a copper-bronze alloy. Good yields in this reaction are limited to halides with electron-attracting substituents. Mechanistic and synthetic work has revealed the... 

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