Teraryl

Fig. 8 Teraryl-substituted a-diimine ligand-based Ni(II) polymerization catalysts...

Table 5 Ethylene polymerizations by teraryl-substituted a-diimine Ni(II) catalysts8...

V. Remote aromatic metalation. An anionic Friedel-Crafts equivalent for the regioselective synthesis of condensed fluorenones from biaryl and m-teraryl 2-amides. /. Org. Chem. 1991, 56,1683-1685. 

The reaction of 2//-pyran-2-ones 24 with aryl methyl ketones in the presence of KOH provides a mixture of 1,3-teraryls 25 and alkylidenc-2//-pyrans 26 (Equation 13) <1998S167>. Likewise, 6-(4-fluorophenyl)-3-cyano-4-(methylthio)-27/-pyran-2-one 27 reacts to afford the corresponding alkylidene 2//-pyran as the sole product (Equation 14) <2001J(P1)1953>. 

Stepwise double coupling of two different arylboronic acids with a dihaloarene afforded one-pot, two-step method for synthesizing unsymmetrical teraryls, quateraryls, and other higher order polyaryls.882 The first total synthesis of dragmacidin D involved a sequential double coupling of two different pinacol 3-indoleboronic esters (ArBpin Equation (207)).882... 

The synthesis of teraryls, quateraryls, and further higher-order polyaryls, and the ever-increasing complexity in the more functionalized materials requires simple and practical methods for synthesizing building blocks (Scheme 33). The transmetalation between an aryllithium, -magnesium, or other metal (Al, Si,Zn)... 

Teraryls are readily synthesized from l,4-his(iodozincio)benzene by consecutive Negishi coupling reactions. Such is feasible because of the different reactivity of the two types of arylzinc reagents, products of the first coupling are less reactive toward the Pd catalyst. ... 

Coupling of aryl iodides and arylboronic acids.6 This Suzuki cross coupling can be effected with this Pd(0) complex as catalyst and Na2CO, as base. It provides a rapid access to m- or p-teraryls. 

Remote metalation of biaryls and m-teraryls provides a general synthesis of substituted and condensed fluorenones (eq47). Similarly, biaryl 0-carbamates undergo remote metalation and anionic Fries rearrangement to 2-hydroxy-2 -carboxamidobiaryls, which are efficiently transformed into dibenzo[fc,i/]pyranones. ... 

Catellani and coworkers [31] observed dramatic effects of added olefins on the product selectivity in Pd-catalyzed/norbornene-mediated reactions of aryl iodides, aryl bromides, and aryl boronic acids in the synthesis of o-teraryls 91 (Scheme 3.23). 

Scheme 3.23 Effects of added olefin on product selectivity in the synthesis of o-teraryls.

It was found that adding diethyl maleate drastically increased the product ratio, favoring the desired cross-coupled product 91 over the homo-coupled products 92 and 93. Under these conditions, a variety of multisubstituted o-teraryls 94 were synthesized with good selectivities in which the Suzuki coupling with aryl boronic acids served as the termination step (Scheme 3.24). The authors argued that the... 

Unrau CM, Campbell MG, Snieckus V (1992) Directed ortho metalation - Suzuki cross coupling connections. Convenient regiospecific routes to functionalized m-and p-teraryls and m-quinquearyls. Tetrahedron Lett 33 2773-2776... 

A tandem phospha Friedel—Crafts reaction has been used to transform dichloro(m-teraryl)phosphine into triarylphosphine derivatives, such as (1), where the curved n-conjugated framework allows extended conjugation over the whole molecule. The reaction of the metallabenzyne (2) with electrophiles shows that it exhibits aromatic... 

Stepwise, double cross-coupling with dihaloarenes provides a method for synthesizing teraryls, quateraryls, and other higher order polyeuyls. lodo-, bromo- and chloroarenes are well differentiated under standard... 

Finally, the lactone concept was extended to the synthesis of two-fold lactone-bridged teraryls which may be suitable precursors for the formation of... 

C2-symmetric teraryls. The synthesis was accomplished by palladium-catalysed intramolecular coupling, with subsequent ester saponification, methyl ether cleavage and two-fold ring closure to give the expected bislactone (Scheme 5.52). ... 

Figure 8.2 Selectively substituted bi- and teraryls accessible by norbornene-mediated palladium-catalyzed multicomponent reactions [362].

Scheme 14.7 The DoM-Suzuki-Miyaura cross-coupling sequence for construction of teraryls [60],...

Catellani [61] reported a palladium/norbomene-catalyzed synthesis of heteroatom-containing o-teraryls from aryl iodides and heteroarenes (including indoles and pyrroles) through double C-H arylation. Fagnou s group [62] applied their own protocol (Pd(II)/Ag(I)/carboxylic acid) to achieve the direct arylation of azaindoles. Itami [63] demonstrated the first iridium-catalyzed C-H arylation of heteroarenes (involving indoles and pyrroles) with aryl halides. 

The second example is the nentral iridium(I)/Me-Duphos complex-catalyzed [2+2+2] cycloaddition [20]. This reaction afforded 1,4-teraryls with two atropisomeric chiralities with excellent enantio- and diastereoselectivity (Scheme 21.17) [20]. 

In 2004, Shibata et al. reported on the atrop-selective biaryl synthesis by iridium-catalyzed [2 + 2 + 2] cycloaddition [8], They developed the synthesis of axially chiral 1,4-teraryls 16 with two atropisomeric chiralities by the neutral iridium(I)/Me-Duphos complex-catalyzed enantio- and diastereoselectivitive [2 + 2 + 2] cycloaddition of a,w-diynes 14, possessing ortho-substituted aryl groups at alkyne termini, with functionalized internal monoynes 15 in high yields with excellent enantio- and diastereoselectivity (Scheme 9.6) [8,9],... 

Not only 1,4-teraryl but also 1,2-teraryl compounds, with two atropisomeric chiralities, could be synthesized via neutral iridium(I)/Me-duphos complex-catalyzed... 

The reaction of 2-methoxynaphthalene-derived 1,6-diyne 43 with alkynyl ester 44 in the presence of a cationic rhodium(I)/Segphos catalyst proceeded with perfect regioselectivity to give axially chiral 1,3-teraryl 45 in good yield and ee value... 

Neutral iridium(I)/chiral bisphosphine complexes are particularly suitable for the enantio- and diastereoselective synthesis of axially chiral teraryl, quin-quearyl, and noviaryl compounds by the enantioselective [2 - - 2 - - 2] cycloaddition reactions of alkynes, possessing bulky aryl groups at the alkyne termini. 

Shibata, T., Fujimoto, T., Yokota, K. and Takagi, K. (2004) Iridium complex-catalyzed highly enantio- and diastereoselective [24-24-2] cycloaddition for the synthesis of axially chiral teraryl compounds. Journal of the American Chemical Society, 126(27), 8382-8383. 

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