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1,4-Diaryl-9H-fluoren-9-ones were prepared by regioselective Suzuki-Miyaura cross-coupling reaction of the bis(triflate) of 1,4-dihydroxy-9H-fluoren-9-one. The reactions proceeded with excellent site selectivity. The first attack occurs at position 1, due to electronic reasons. [ABSTRACT FROM AUTHOR]

Arylated flavones were prepared by Suzuki-Miyaura reactions of 6-bromo-3-(trifluoro-sulfonyloxy)flavone. The reactions proceeded with very good chemoselectivity in favor of position 3. [ABSTRACT FROM AUTHOR]

A ring-ring transformation in the series of spiro[indole- 3,5'-pyrimido[4,5-b]quinoline]-2,2',4'-trione derivatives prepared by a three-component reaction of (thio)barbituric acids, electronrich aromatic amines, and isatins was observed. [ABSTRACT FROM AUTHOR]

Different spectroscopic methods were applied in situ as well as ex situ to elucidate the mode of action of the Lewis acids TiCl4 and trimethylsilyl trifluoromethanesulfonate (TMSOTf) in the formal [3+3] cyclization reaction of a 1,3-bis(silyloxy)-1,3-butadiene with fluorinated ketenacetales. Different products were formed depending on the type of Lewis acid employed, which can be explained by their completely different interaction with the ketenacetale. Results of attenuated total reflection infrared (ATR-IR) and UV/vis spectroscopic studies revealed that TMSOTf interacts with only one site of the ketenacetale, forming an ionic species. In contrast, TiCl4 forms a bischelate complex, which was confirmed by using X-ray crystal structure analysis. Both reaction pathways were studied by simultaneously applying in situ ATR-IR/UV/vis spectroscopy in a specifically developed reaction cell. During cooling and subsequent heating of the reaction mixture, formation and structural changes of different intermediates were observed, in particular in the case of the TMSOTf catalyzed reaction. Although the TiCl4 mediated reaction proceeds in only one step, the TMSOTf route comprises two reaction steps. In situ spectroscopic results revealed that the applied workup procedure influences product formation and distribution as well. [ABSTRACT FROM AUTHOR]

Site-selective Suzuki-Miyaura reactions of 2,3,5-tribromo- N-methylpyrrole afforded 5-aryl-2,3-dibromo- N-methylpyrroles. These products were transformed into 2,5,6-trisubstituted N-methylindoles by twofold Heck reactions and subsequent 6?-electrocyclization-dehydrogenation reactions. [ABSTRACT FROM AUTHOR]

The [4+2] cycloaddition of 1-ethoxy-2-fluoro-1,3-bis(trimethylsilyloxy)-1,3-diene with dimethyl acetylenedicarboxylate (DMAD) afforded dimethyl 4-fluoro-3,5-dihydroxyphthalate. Site-selective Suzuki-Miyaura reactions of its bis(triflate) provide a convenient approach to 3,5-diaryl-4-fluorophthalates. [ABSTRACT FROM AUTHOR]

The first Suzuki-Miyaura reactions of 2,3,5-tribromothiophene are reported. These reactions provide a convenient and site-selective approach to 5-aryl-2,3-dibromothiophenes, 2,5-diaryl-3-bromothiophenes, and 2,3,5-triarylthiophenes. [ABSTRACT FROM AUTHOR]

N-Methyl-2,3,4,5-tetrabromopyrrole is transformed into a variety of alkynyl-substituted pyrroles by regioselective Sonogashira cross-coupling reactions. In this context, the synthesis of the first tri- and tetra(1-alkynyl)pyrroles is reported. [ABSTRACT FROM AUTHOR]

Abstract: Chlorinated phenols, benzophenones, and butenolides are prepared by various one-pot cyclization reactions of the first 4-chloro-1,3-bis(trimethylsilyloxy)-1,3-butadiene. [Copyright &y& Elsevier]

5-Cyano-1,3-dioxoalkanes were prepared by reaction of 1,3-dicarbonyl dianions with bromoacetonitrile. [ABSTRACT FROM AUTHOR]

Abstract: Spirocyclic butenolides were efficiently prepared by a ring closing metathesis strategy. [Copyright &y& Elsevier]

4-(Silyloxy)benzopyrylium triflates can be readily generated in situ by reaction of chromones with trialkylsilyl-tri�fluoromethanesulfonate. Domino reactions of silyl enol ethers with benzopyrylium triflates - derived from chromones, 3-cyanochromones and 3-formylchromones - allow an efficient synthesis of a variety of carba- and heterocycles. [ABSTRACT FROM AUTHOR]

4-Aryl-2-imino-2H-selenazolines have been prepared by a reaction of α-(selenocyanato)acetophenones with anilines. [ABSTRACT FROM AUTHOR]

Abstract: Domino reactions of amidines with 2-alkylidenetetrahydrofurans, prepared by cyclization of 1,3-dicarbonyl dianions or 1,3-bis-silyl enol ethers with various dielectrophiles, provided an efficient access to 4-(3-hydroxyalkyl)pyrimidines. [Copyright &y& Elsevier]

A variety of furan-2-ylacetates have been prepared by dehydrogenation of monocyclic 2-alkylidene-tetrahydrofurans, which are readily available by cyclizations of open-chained 1,3-dicarbonyl dianions with 1-bromo-2-chloroethane. 5′H-[2,3′]Bifuranyl-2′-ones are available based on sequential ‘cyclization]dehydrogenation’ reactions of α-acetyl-γ-butyrolactones. A variety of 7-(alkoxycarbonyl)-benzofurans and 7-(alkoxycarbonyl)-2,3-dihydrobenzofurans were prepared by a cyclization] dehydrogenation strategy. These reactions rely on cyclizations of 2-oxocycloalkane-1-carboxylate-derived 1,3-dicarbonyl dianions (‘free dianions’) or 1,3-bis-silyl enol ethers (‘masked dianions’) with various 1,2-dielectrophiles. [ABSTRACT FROM AUTHOR]

Bromination and subsequent Suzuki reactions of 2-alkylidenetetrahydrofurans, readily available by [3+2] cyclizations, afforded 1′-(2″-methoxyphenyl)-2-alkylidenetetrahydrofurans. Treatment of the latter with boron tribromide and subsequent addition of water resulted in the chemoselective formation of functionalized benzofurans containing a remote bromide functionality. The products are formed by a new domino ‘ring-cleavage-deprotection-cyclization’ reaction. The addition of an aqueous solution of potassium tert-butoxide, rather than water, afforded saturated analogues of calycine by a ‘ring-cleavage-deprotection-ring-closure-lactonization’ reaction. [ABSTRACT FROM AUTHOR]

Abstract: A number of pulvinic acid natural products were prepared based on Suzuki cross coupling reactions of α-hydroxy-γ-alkylidenebutenolides which are readily available by cyclization of 1,3-bis-silyl enol ethers with oxalyl chloride. The formal total synthesis of pulvinic acid, atromentic acid, gomphidic acid and of 4-hydroxypulvinic acid, 4′-hydroxypulvinic acid and iso-gomphidic acid are reported. In addition, total syntheses of pinastric acid, xerocomic acid and variegatic acid were accomplished. [Copyright &y& Elsevier]

α-Hydroxy-γ-alkylidenebutenolides were efficiently fimctionalized by Suzuki cross-coupling reactions via the corresponding enol triflates. The natural product vulpinic acid was prepared by this methodology. [ABSTRACT FROM AUTHOR]

3-Aryl-2-nitroindoles were prepared via CH-activation reactions of N-methyl-2-nitroindole. [ABSTRACT FROM AUTHOR]

The palladium(0)-catalyzed Suzuki cross-coupling reaction of the bis(triflates) of 2′,4-dihydroxybenzophenones afforded 2′,4-diarylbenzophenones. The reactions proceeded with very good site selectivity. The first attack occurred at carbon atom C-4. [ABSTRACT FROM AUTHOR]

A variety of 2-arylthio-4-methoxybenzoates are regio�selectively prepared by the first formal [3+3] cyclocondensations of 3-arylthio-1-trimethylsilyloxybuta-1,3-dienes with 3-oxo-ortho�esters. [ABSTRACT FROM AUTHOR]

Functionalized benzophenones were prepared by domino ‘Michael-retro-Michael-aldol’ reactions of 1,3-bis-silyl enol ethers with 3-formylchromones. [Copyright &y& Elsevier]

Pharmacologically relevant 5-thioxo-6H-imidazo[1,2-c]quinazolines and 5-oxo-6H-imidazo[1,2-c]quinazolines were prepared by sequential reactions of α-aminoketones with 2-isothiocyanatobenzonitrile and 2-isocyanatobenzonitrile, respectively. [Copyright &y& Elsevier]

Benzopyrano[2,3-b]pyridines were efficiently prepared by condensation of 1,3-bis-silyl enol ethers with 3-cyanobenzopyrylium triflates and subsequent domino ‘retro-Michael–lactonization–aldol’ reactions. [Copyright &y& Elsevier]

The reaction of butadienes (II) and (IV) with buten-2-one (I) affords trichloromethyl-substituted salicylates (III) or corresponding cyclohexenones (VIII) depending on the type of Lewis acid employed. [ABSTRACT FROM AUTHOR]

3-Acyl-2-alkenylfurans were prepared by ‘Feist-Benary cyclocondensation’ of (2,4-dioxobutylidene)-phosphoranes with chloracetaldehyde and α-haloketones and subsequent Wittig reactions. [ABSTRACT FROM AUTHOR]

The condensation of 1,3-dicarbonyl dianions with α-azidoketones afforded open-chained condensation products that were transformed into pyrroles by Staudinger-aza-Wittig reactions and the subsequent treatment with trifluoroacetic acid. [ABSTRACT FROM AUTHOR]

Abstract: Functionalized 2,5-dihydrobenzo[b]oxepines and 5,6-dihydro-2H-benzo[b]oxocines were prepared based on a ‘[3+3] cyclization-olefin-metathesis’ strategy. [Copyright &y& Elsevier]

Abstract: Various aryl-substituted anthraquinones were prepared by palladium(0)-catalyzed Suzuki-Miyaura cross-coupling reactions of the bis(triflate) of 1,3-dihydroxyanthraquinone. A very good site-selectivity in favor of position 1 was observed which can be explained by the electronic influence of the neighboring carbonyl group. [Copyright &y& Elsevier]

Abstract: A variety of heterocyclic spiranes were prepared by cyclization of dinucleophiles with 1,1-bis(tosyloxymethyl)cyclopropane and -cyclobutane. [Copyright &y& Elsevier]

Abstract: The cyclization of hydrazone dianions with diethyl oxalate afforded pyrazole-5-carboxylates. [Copyright &y& Elsevier]

Abstract: Functionalized and sterically encumbered diaryl sulfides were prepared based on [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-dienes. [Copyright &y& Elsevier]

Abstract: Functionalized fluorenones were prepared by sequential ‘[3+3] cyclization–Suzuki cross-coupling/Friedel–Crafts acylation’ reactions. [Copyright &y& Elsevier]

The cyclization of thiosemicarbazide with α-bromoacetophenone can result in the formation of isomeric 1,3,4-thiadiazines and two different thiazoles. We studied the use of 4-methyl- and 4-ethylthiosemicarbazide as dinucleophilic building blocks. In this context, we observed an unprecedented rearrangement of a 2-hydrazono-2,3-dihydrothiazole to a 1,3,4-thiadiazine. While ring contractions of 1,3,4-thiadiazines to thiazoles are quite common, ring enlargements are new. The course of the reaction depends on the substitution pattern of the substrate. [ABSTRACT FROM AUTHOR]

Abstract: Arylated anthraquinones were prepared by Suzuki–Miyaura reactions of the bis(triflates) of various 1,3-(dihydroxy)anthraquinones. While the reactions of the bis(triflates) of parent 1,3-(dihydroxy)anthraquinone and of 2-chloro-1,3-di(hydroxy)anthraquinone proceeded with very good site-selectivity, the corresponding reactions of the bis(triflate) of 2-fluoro-1,3-diarylanthraquinones were not site-selective, which was explained based on the π-donating effect of the fluorine atom. [Copyright &y& Elsevier]

Abstract: Arylated 1-methyl-1H-indoles were prepared by Suzuki–Miyaura cross-coupling reactions of 2,3-dibromo-1-methyl-1H-indole and 2,3,6-tribromo-1-methyl-1H-indole. The reactions proceed with very good regioselectivity in favour of position 2. [Copyright &y& Elsevier]

Abstract: Functionalized trifluoromethyl-substituted salicylates have been synthesized based on AlCl3-mediated cyclocondensation reactions using 4,4-dimethoxy-1,1,1-trifluorobut-3-en-2-one and 1,3-bis(silyloxy)-1,3-butadienes. Simultaneous in situ ATR-FTIR/UV–vis spectroscopic measurements were carried out for mechanistic studies. Real-time in situ spectroscopic investigations reveal the formation of an aluminum trichloride bidentate-butenone adduct as intermediate. The observed band shifts in the respective UV–vis spectra in consequence of complex formation could be explained by theoretical calculations. Lewis acidic solids (Al2O3 and TiO2) were also successfully utilized. Due to the strong substrate adsorption on the solids detected by UV–vis-DRS and FTIR transmission spectroscopy the obtained yields were rather modest. [Copyright &y& Elsevier]

Abstract: Suzuki–Miyaura reactions of 2,6-dichlorobenzoxazole provide a convenient access to arylated benzoxazoles. The reactions proceed with excellent site-selectivity in favour of position 2, due to electronic reasons. [Copyright &y& Elsevier]

Abstract: The insertion of fluorinated 1,3-dicarbonyl compounds to benzyne resulted in regioselective formation of various fluorinated 1,5-dicarbonyl compounds which are not readily available by other methods. Products include 2-trifluoroacetyl- and 2-(perfluoroalkanoyl)phenylacetic estres, 2-fluoro-2-phenylacetic esters, 1-aryl-2-(2-trifluoroacetylphenyl)ethan-1-ones and other derivatives. [Copyright &y& Elsevier]

Abstract: A variety of trifluoromethylated bi- and terphenyls were prepared by site-selective Suzuki–Miyaura cross-coupling reactions of various dihalogenated trifluoromethyl-substituted benzene derivatives. The reactions proceed with excellent site-selectivities. [Copyright &y& Elsevier]

Abstract: A concise and efficient approach to a series of chromen-4-ones with fused thiophene ring has been developed using the Suzuki–Miyaura reaction of bromothiophene-2- and 3-carboxylates with 2-methoxyboronic acids and subsequent cyclization of prepared alkyl (2-methoxy)aryl thiophene-2- and 3-carboxylates under the action of BBr3/KOtBu. Starting bromothiophenes are easily obtained from corresponding commercially available aminothiophenes by diazotization/bromination reaction. [Copyright &y& Elsevier]

Abstract: Arylated xanthones were prepared by site-selective Suzuki–Miyaura reactions of the bis(triflate) of 1,3-dihydroxyxanthone. The first attack occurs at the sterically less encumbered position 3. The site-selectivity is in contrast to the bis(triflate) of 1,3-dihydroxyanthraquinone. [Copyright &y& Elsevier]

Abstract: Suzuki–Miyaura reactions of 4-trifluoromethylsulfonyloxy-6-bromocoumarin provide a convenient access to arylated coumarins. The reactions proceed with excellent chemoselectivity in favour of position 4. [Copyright &y& Elsevier]

Suzuki Miyaura reactions of 2,3-dibromo-1 H-inden-1-one afforded a wide range of arylated 1 H-inden-1-ones. Sonogashira cross-coupling reactions gave alkynylated indenones. The reactions proceeded with very good regioselectivity in the less sterically hindered and more electron-deficient position 3. [ABSTRACT FROM AUTHOR]

Abstract: The palladium(0)-catalyzed Suzuki cross-coupling reactions of the bis(triflates) of 1,3- and 1,4-dihydroxythioxanthone afforded various aryl-substituted thioxanthones. While the Suzuki reactions of the bis(triflate) derived from 1,3-dihydroxythioxanthone proceeded by site-selective attack in favor of position 3, the reactions of the bis(triflate) of 1,4-dihydroxythioxanthone proceeded in favor of position 1. The site-selectivity is controlled by steric and electronic parameters. [Copyright &y& Elsevier]

Abstract: Permethylated 1,3,5-tri- and 1,3,5,7-tetracarbonyl compounds were prepared and structurally characterized. 2,2,4,4-Tetramethyl-3,5-dioxoesters were prepared by condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with acid chlorides and subsequent reaction with methyl iodide. 2,2,4,4,6,6-Hexa-substituted 3,5-dioxopimelates were prepared by condensation of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with methyl 3-chloro-3-oxopropanoate and subsequent methylation. The use of caesium carbonate as the base for the methylation proved to be important to achieve good yields. The conformation of the products was studied by experimental and theoretical methods (DFT calculations). [Copyright &y& Elsevier]

Abstract: The reaction of 1,3,5-triazine and 2,4,6-tri(trifluoromethyl)-1,3,5-triazine with in situ generated 1-substituted 5-amino-1H-imidazoles led to a set of functionalized purines. The developed practical route could serve as a fundament for the preparation of related ADA inhibitors. [Copyright &y& Elsevier]

Abstract: 4-Chloro-3-(trifluoroacetyl)- and 4-chloro-3-(methoxalyl)coumarins react with electron-rich aminoheterocycles, dimethyl 1,3-acetonedicarboxylate, hydrazines, alkyl thioglycolates, and methyl sarcosinate to give a variety of 3,4-heteroannulated coumarins. The starting materials were prepared by the reaction of 4-hydroxycoumarin with trifluoroacetic anhydride and methyl 2-chloro-2-oxoacetate in the presence of trimethylsilylchloride. An NMR study and X-ray crystallographic analysis are reported. [Copyright &y& Elsevier]

Abstract: The reaction of electron-rich aminoheterocycles with 3-acyl- and 3-formylindoles results in indole ring opening and cyclocondensation to give heteroannulated pyridines, which can be regarded as purine isosteres. The transformations reported herein represent rare examples of domino reactions, which include the cleavage of an indole moiety. [Copyright &y& Elsevier]

Abstract: Suzuki–Miyaura reactions of N-protected tribromopyrazoles were studied. The reactions proceed with excellent site-selectivity. The first attack occurs at position 5, while the second and third attack occur at positions 3 and 4, respectively. A variety of 3,4,5-triaryl-pyrazoles, 3,5-diaryl-4-bromopyrazoles, and 5-aryl-3,4-dibromopyrazoles were efficiently prepared. The products are not readily available by other methods. [Copyright &y& Elsevier]