Palladium arene containing

Kamikawa T, Hayashi T (1997) Control of reactive site in palladium-catalyzed Grignard crosscoupling of arenes containing both bromide and triflate. Tetrahedron Lett 38 7087-7090... 

Two regioselective palladium-catalyzed methods have been developed for the direct C-H arylation of oxazole at C-5 or C-2 using aryl and heteroaryl bromides, chlorides, iodides, and tri-flates (eq SS). " Under optimized conditions, minor amounts (<10%) of the bis(arylated) product are observed. The reaction works well with arenes containing electron-donating or electron-withdrawing substituents. 

Oxidation of benzoquinones and naphthoquinones by palladium diacetate in arene-containing acetic acid gave the corresponding aryl-substituted quinones (eq 70). Treatment of 1,4-naphthoquinone with aromatic heterocycles, for example furfural, 2-acetylfuran, 2-acetylthiophene, and 4-pyrone, yielded the corresponding 2-heteroaryl-substituted 1,4-naphthoquinones. 

Over the last decade, the chemistry of the carbon-carbon triple bond has experienced a vigorous resurgence [1]. Whereas construction of alkyne-con-taining systems had previously been a laborious process, the advent of new synthetic methodology based on organotransition metal complexes has revolutionized the field [2]. Specifically, palladium-catalyzed cross-coupling reactions between alkyne sp-carbon atoms and sp -carbon atoms of arenes and alkenes have allowed for rapid assembly of relatively complex structures [3]. In particular, the preparation of alkyne-rich macrocycles, the subject of this report, has benefited enormously from these recent advances. For the purpose of this review, we Emit the discussion to cychc systems which contain benzene and acetylene moieties only, henceforth referred to as phenylacetylene and phenyldiacetylene macrocycles (PAMs and PDMs, respectively). Not only have a wide... 

Condensation of aryl halides with various active methylene compounds is readily promoted by catalytic action of palladium to give the corresponding arene derivatives containing a functionalized ethyl group [7]. Yamanaka et al. extended this chemistry to haloazoles including oxazoles, thiazoles and imidazoles [8]. Thus, in the presence of Pd(Ph3P)4,2-chlorooxazole was refluxed with phenylsulfonylacetonitrile and NaH to form 4,5-diphenyl-a-phenylsulfonyl-2-oxazoloacetonitrile, which existed predominantly as its enamine tautomer. In a similar fashion, 4-bromooxazole and 5-bromooxazole also were condensed with phenylsulfonylacetonitrile under the same conditions. 

Termination of cascade carbopalladation sequences by arylation can play a major role in systems that form a reasonably long-lived palladium intermediate and contain a suitably functionalized arene moiety in the vicinity of the organopalladium function. In particular, neopentylpalladium intermediates have been found to intramolecularly attack an adjacent arene moiety. For example, iodoarenes 149 with electron-withdrawing substituents in the... 

Heterometal alkoxide precursors, for ceramics, 12, 60-61 Heterometal chalcogenides, synthesis, 12, 62 Heterometal cubanes, as metal-organic precursor, 12, 39 Heterometallic alkenes, with platinum, 8, 639 Heterometallic alkynes, with platinum, models, 8, 650 Heterometallic clusters as heterogeneous catalyst precursors, 12, 767 in homogeneous catalysis, 12, 761 with Ni—M and Ni-C cr-bonded complexes, 8, 115 Heterometallic complexes with arene chromium carbonyls, 5, 259 bridged chromium isonitriles, 5, 274 with cyclopentadienyl hydride niobium moieties, 5, 72 with ruthenium—osmium, overview, 6, 1045—1116 with tungsten carbonyls, 5, 702 Heterometallic dimers, palladium complexes, 8, 210 Heterometallic iron-containing compounds cluster compounds, 6, 331 dinuclear compounds, 6, 319 overview, 6, 319-352... 

An interesting application of the Fujiwara-Moritani/oxidative Heck reaction for the synthesis of benzo furans was recently reported by the Stoltz lab [31]. A variety of allyl phenyl ethers (all containing electron-rich aryl components) react with 10 mol% palladium acetate, 20 mol% ethyl nicotinate, 20 mol% sodium acetate, and one equivalent of benzoquinone at 100°C to provide benzofurans in 52-79% yield (e.g. 16—>17). The mechanism of this transformation begins with arene palladation of Pd(II) followed by olefin insertion, p-hydrogen elimination, and olefin isomerization to the thermodynamically favored benzofuran product. The resulting Pd(0) species is then oxidized to Pd(ll) thus regenerating the active catalyst. 

Palladium and copper-catalyzed arylation of C-H bonds by aryl halide reagents is reviewed. The emphasis of the review is on directing-group-containing arene and alkane arylation catalyzed by palladium and on sp2 C-H bond arylation catalyzed by copper. Literature up to early 2009 is covered. 

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