具有Frétchet树枝结构的新型酞菁锌(Ⅱ)配合物:四-{3,5-二-[3,5-二-(4-羧基苯甲氧基)苯甲氧基]-苯甲氧基}酞菁锌(Ⅱ)的合成与表征

报道了一种新型Frétchet树枝配体取代酞菁锌(II)配合物:四-{3,5-二-[3,5-二-(4-羧基苯甲氧基)苯甲氧基]-苯甲氧基}酞菁锌(II)的合成与表征.首先将对氰基苄溴与3,5-二羟基苯甲醇通过Frétchet反应合成3,5-[二-(4-氰基苯甲氧基)]苯甲醇(1),1与四溴化碳和三苯基膦在四氢呋喃中反应合成3,5-二-(4-氰基苯甲氧基)苄溴(2),2与3,5-二羟基苯甲醇反应合成3,5-二-[3,5-二-(4-氰基苯甲氧基)苯甲氧基]苯甲醇(3),接着,3与4-硝基邻苯二甲腈合成"前驱物"四-{3,5-[二-(4-氰基苯甲氧基)]}苯甲氧基邻苯二甲腈(4),然后以1,8-二氮杂双环[5.4.0]十一碳-7-烯(DBU)为催化剂,醋酸锌为模板剂,4通过缩聚反应合成氰基端基的Frétchet树枝配体取代酞菁锌四-{3,5-二-[3,5-二-(4-氰基苯甲氧基)苯甲氧基]-苯甲氧基}锌酞菁配合物5,最后,5的氰基端基在NaOH溶液中水解为相应的以羧基端基Frétchet树枝配体取代酞菁锌:四-{3,5-二-[3,5-二-(4-羧基苯甲氧基)苯甲氧基]-苯甲氧基}酞菁锌(II)(6).采用元素分析,IR,1H NMR,ESI-MS和MALDI-TOF-MS表征所有化合物的结构,通过UV/Vis,稳态和瞬态荧光光谱法研究了5和6的光物理性质.5和6是一类性能较好的树枝状酞菁光敏剂.     

新型树枝状分子3,5-二[3,5-二(4-羧基苯甲氧基)苯甲氧基]苯甲醇的合成

采用收敛法,以对氰基苄溴和3,5-二羟基苯甲醇为原料,依次合成了端基为腈基的芳醚树枝状分子3,5-二(4-腈基苯甲氧基)苯甲醇(4)和3,5-二[3,5-二(4-腈基苯甲氧基)苯甲氧基]苯甲醇(6);4与6分别经水解制得以羧基为端基的新型芳基苄醚树枝状分子3,5-二(4-羧基苯甲氧基)苯甲醇和3,5-二[3,5-二(4-羧基苯甲氧基)苯甲氧基]苯甲醇,其结构经UV-Vis,1H NMR,IR,MS和元素分析表征.     

Novel first-generation dendrimers on calix[4]resorcinol core equipped with multiple triazole units

Novel first-generation dendrimers on the calix[4]resorcinol core with four branches each containing multiple 1,2,3-triazole units have been synthesized in one-step by acid catalyzed condensation of resorcinols with a new aldehyde dendron, namely, 4-{3,5-bis[(1-benzyl-1H-1,2,3-triazol-4-yl)- methoxy]benzyloxy}benzaldehyde (obtained by alkyne–azide cycloaddition). The reaction proceeds stereoselectively to form rccc-diastereoisomers in high yields.     

Magnetic properties of dendritic polycarbenes substituted by bulky peripheral groups

As photo-reactive precursors of high-spin organic compounds sterically separated from surroundings by bulky peripheral groups, diphenyldiazomethane derivatives substituted by tetrakis{3,5-bis(benzyloxy)benzyloxy} groups 1, by tetrakis[3,5-bis{3′,5′-bis(benzyloxy)benzyloxy}bezyloxy] groups 2, and nonakisdiazo compound associated with ferromagnetic spin couplers substituted by dodecakis{3,5-bis(benzyloxy)benzyloxy} groups 3, were prepared and their magnetic properties after irradiation in their own condensed films were investigated. Field dependences of magnetization and temperature dependences of χT value after irradiation of 1 and 2 clearly exhibited that spin centers i.e., diphenylcarbene parts of 1 and 2 were magnetically isolated from surrounding molecules each other by steric hindrance of the peripheral bulk substituents even in the neat films. In the case of 3, some part of molecules interacted antiferromagnetically with neighboring molecules but a fatal strong antiferromagnetic interaction was also avoided.     

Process development and large-scale synthesis of NK1 antagonist

A scaleable synthetic route is described to obtain 2-(4-acetylpiperadin-1-yl)-6-[3,5-bis(trifluoromethyl)phenylmethyl]-4-(2-methylphenyl)-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,5]oxazocin-5-one (1, KRP-103) as a neurokinin (NK)(1) antagonist. The key step in the synthesis is the intramolecular cyclization of N-[3,5-bis(trifluoromethyl)phenylmethyl]-N-(3-hydroxypropyl)-4-chloro-6-(2-methylphenyl)-2-methylthiopyrimidine-5-carboxamide (15) which was obtained by amide formation between 4-(2-methylphenyl)-2-methylthio-6-oxo-1,6-dihydropyrimidine-5-carboxylic acid (8) and 3-[3,5-bis(trifluoromethyl)phenylmethylamino]-1-propanol (3). Treatment of 15 with 1,8-diazabicyclo[5,4,0]undec-7-ene provided 6-[3,5-bis(trifluoromethyl)phenylmethyl]-4-(2-methylphenyl)-2-methylthio-6,7,8,9-tetrahydro-5H-pyrimido[4,5-b][1,5]oxazocin-5-one (6). This intermediate (6) is transformed into the candidate compound (1) by two steps; oxidation, and substitution reaction of the resultant sulfone (7) with 1-acetylpiperazine. This synthetic method is free of chromatographic purification and is amenable to large scale synthesis.     

A dendrimer approach to high-spin polycarbenes. Conversion of connectivity from disjoint to non-disjoint by perturbation of nonbonding molecular orbital coefficients

[structure: see text] Pentakis(diazo) compound was prepared by coupling 3,5-bis[4-[diazo(4-tert-butyl-2,6-dimethylphenyl)methyl]-3,5-dibromophenylethynyl]phenylacetylene with bis(4-iodo-2,6-dimethylphenyl)diazomethane under Sonogashira reaction conditions. Pentakis(carbene) generated by irradiation of the pentakis(diazo) compound was shown to have a high-spin state with S = 4.4 at 2.0 K.     

Decorating poly(alkyl aryl-ether) dendrimers with metallacarboranes

A new family of polyanionic poly(alkyl aryl-ether) metallodendrimers decorated with four and eight cobaltabisdicarbollide units have been obtained in high yield by the ring-opening reaction of cyclic oxonium [3,3'-Co(8-(C(2)H(4)O)(2)-1,2-C(2)B(9)H(10))(1',2'-C(2)B(9)H(11))] with alkoxides formed by deprotonation of terminal alcohols in the α,α'-bis[3,5-bis(hydroxymehyl)phenoxy]-p-xylene, α,α'-bis[3,5-bis(hydroxymehyl)phenoxy]-m-xylene, α,α'-bis[3,5-bis-[3,5-bis(hydroxymethyl)phenoxy]methylen]phenoxy]-p-xylene, and α,α,'-bis[3,5-bis-[3,5-bis(hydroxymethyl)phenoxy]methylen]phenoxy]-m-xylene dendrimers. The crystal structure of the precursor α,α'-bis[3,5-bis(chloromethyl)phenoxy]-p-xylene is also described. Final products are fully characterized by FTIR, NMR, UV-vis spectroscopies and elemental analysis. For metallodendrimers, the UV-vis absorptions have been a good tool for estimating the experimental number of cobaltabisdicarbollide units peripherally attached to the dendrimeric structure and consequently to corroborate the complete functionalization of the dendrimers.     

Decoupling optical and potentiometric band gaps in pi-conjugated materials

Syntheses, optical spectroscopy, potentiometric studies, and electronic structural calculations are reported for two classes of conjugated (porphinato)metal oligomers that feature a meso-to-meso ethyne-bridged linkage topology. One set of these systems, bis[(5,5'-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethyne (DD), 5,15-bis[[5'-10',20'-bis[3,5-di(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DDD), and 5,15-bis[[15' '-(5'-10',20'-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5' '-10' ',20' '-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II)]ethyne]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DDDDD), constitute highly soluble analogues of previously studied examples of this structural motif having simple 10,20-diaryl substituents, while a corresponding set of conjugated oligomers, [(5-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5'-15'-ethynyl-10',20'-bis[10,20-bis(heptafluoropropyl)porphinato)zinc(II)]ethyne (DA), 5,15-bis[[5'-10',20'-bis[3,5-di(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethynyl]-10,20-bis(heptafluoropropyl)porphinato]zinc(II) (DAD), and 5,15-bis[[15' '-(5'-10',20'-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5' '-(10' ',20' '-bis(heptafluoropropyl)porphinato)zinc(II)]ethyne]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DADAD), features alternating electron-rich and electron-poor (porphinato)zinc(II) units. Electrooptic and computational data for these species demonstrate that it is possible to engineer conjugated oligomeric structures that possess highly delocalized singlet (S1) excited states yet manifest apparent one-electron oxidation and reduction potentials (E1/20/+ and E1/2-/0 values) that are essentially invariant with respect to those elucidated for their constituent monomeric precursors.     

Ring-opening reactions of oxabicyclic alkene compounds: enantioselective hydride and ethyl additions catalyzed by group 4 metals

Titanium and zirconium catalysts selectively catalyze either the ethyl or hydride addition to [2.2.1] 4, 5-bis(methoxymethyl)-7-oxabicycloheptene (6); the ring-opened products formed depend on catalyst, temperature, alkylaluminum reagent, and the concentration of alkylaluminum. Bis(neoisomenthylindenyl)zirconium dichloride catalyzes the ethyl addition ring-opening of 6 to produce (1R,2S,3S,6R)-2, 3-bis(methoxymethyl)-6-ethylcyclohex-4-enol (7) in 96% ee. Zirconium catalysts catalyze the ring-opening of [3.2.1] 2, 4-dimethyl-3-(benzyloxy)-8-oxabicyclo-6-octene (7) when ethylmagnesium bromide is used as a reagent. Both hydride and ethyl addition products are obtained at all conditions studied. Bis(neoisomenthylindenyl)zirconium dichloride catalyzes the ethyl addition ring-opening of 7 to produce (1S,2R,3S,4S,7S)-2, 4-dimethyl-3-(benzyloxy)-7-ethyl-5-cyclohexen-1-ol (8) in 48% ee.     

Chiral Cyclopentane-Based Mimics of D-myo-Inositol 1,4,5-Trisphosphate from D-Glucose

Two routes from D-glucose to chiral, ring-contracted analogs of the second messenger D-myo-inositol 1,4,5-trisphosphate are described. Methyl alpha-D-glucopyranoside was converted by an improved procedure into methyl 4,6-O-(p-methoxybenzylidene)-alpha-D-glucopyranoside (6) and thence into methyl 2-O-benzyl-3,4-bis-O-(p-methoxybenzyl)-alpha-D-gluco-hexodialdopyranoside (1,5) (14) in four steps. In the first ring-contraction method 14 was converted into methyl 2-O-benzyl-6,7-dideoxy-3,4-bis-O-(p-methoxybenzyl)-alpha-D-gluco-hept-6-enopyranoside (1,5) (15), which on sequential treatment with Cp(2)Zr(n-Bu)(2) followed by BF(3).Et(2)O afforded a mixture of (1R,2S,3S,4R,5S)-3-(benzyloxy)-4-hydroxy-1,2-bis[(p-methoxybenzyl)oxy]-5-vinylcyclopentane (16) and its 4S,5R diastereoisomer 17. Removal of the p-methoxybenzyl groups of 16 and subsequent phosphorylation and deprotection afforded the first target compound, (1R,2R,3S,4R,5S)-3-hydroxy-1,2,4-tris(phosphonooxy)-5-vinylcyclopentane (3). In the second route, intermediate 14 was subjected to SmI(2)-mediated ring contraction to give (1R,2S,3S,4R,5S)-3-(benzyloxy)-4-hydroxy-5-(hydroxymethyl)-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (20). Benzylation of 20 provided (1R,2S,3S,4R,5S)-3-(benzyloxy)-6-[(benzyloxy)methyl]-4-hydroxy-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (22) and (1R,2S,3S,4R,5S)-3,4-bis(benzyloxy)-5-(hydroxymethyl)-1,2-bis[(p-methoxybenzyl)oxy]cyclopentane (21), which were elaborated to the target trisphosphates (1R,2R,3S,4R,5S)-3-hydroxy-5-(hydroxymethyl)-1,2,4-tris(phosphonooxy)cyclopentane (4) and (1R,2S,3R,4R,5S)-1,2-dihydroxy-3,4-bis(phosphonooxy)-5-[(phosphonooxy)methyl]cyclopentane (5), respectively. Both 3 and 4 mobilized intracellular Ca(2+), but 4 was only a few fold less potent than D-myo-inositol 1,4,5-trisphosphate, demonstrating that effective mimics can be designed that do not bear a six-membered ring.     

Synthetic study of optically active and C2-symmetric novel ligand, 7,8-bis(benzyloxy)bicyclo[2.2.2]octa-2,5-diene and a tricarbonyliron complex

The 7,8-bis(benzyloxy)bicyclo[2.2.2]octa-2,5-diene derivatives have been synthesized via Diels-Alder reaction of optically active 5,6-bis(benzyloxy)cyclohexa-1,3-diene and dienophiles. The corresponding tricarbonyliron complexes have also been synthesized in enantiomerically pure form.     

Synthesis of alternating polystyrene/poly(ethyleneoxide) branched polymacromonomers

Newly designed PS/PEO alternating branched polymacromonomers have been obtained by polycondensation of alpha-dicarboxy-functionalized polystyrene and alpha-dihydroxy-functionalized polyethyleneoxide. 4-[3,5-Bis(methoxycarbonyl)phenoxymethyl]benzyl bromide was used as atom-transfer radical polymerization (ATRP) initiator for the synthesis of alpha-dicarboxy functionalized polystyrenes. These macromonomers possess low polydispersities and molecular weights in the range of 7000 to 100,000, as proved by gel permeation chromatography (GPC) and 1H NMR. Alpha-dihydroxy functionalized polyethyleneoxide (PEO) was synthesized by treatment of monofunctionalized PEO with 3,5-bis(benzyloxy)benzoyl chloride. Polycondensation of the alpha-dicarboxy PS with the alpha-dihydroxy PEO in solution or in bulk resulted in alternating PS/PEO polymacromonomers, which were effectively purified from the unreacted macromonomers and characterized by using 1H NMR, GPC, thermal analysis, and optical microscopy. Light-scattering measurements in organic solvents like THF or dioxane have shown that these polymacromonomers form stable micelles.     

Lanthanide-based coordination polymers assembled from derivatives of 3,5-dihydroxy benzoates: syntheses, crystal structures, and photophysical properties

Two new aromatic carboxylic acids, namely, 3,5-bis(benzyloxy)benzoic acid (HL1) and 3,5-bis(pyridine-2-ylmethoxy)benzoic acid (HL2), have been prepared by replacing the hydroxyl hydrogens of 3,5-dihydroxy benzoic acid with benzyl and pyridyl moieties, respectively. The anions derived from HL1 and HL2 have been used for the support of a series of lanthanide coordination compounds [Eu(3+) = 1-2; Tb(3+) = 3-4; Gd(3+) = 5-6]. The new lanthanide complexes have been characterized on the basis of a variety of spectroscopic techniques in conjunction with an assessment of their photophysical properties. Lanthanide complexes 2, 4, and 6, which were synthesized from 3,5-bis(pyridine-2-ylmethoxy)benzoic acid, were structurally authenticated by single-crystal X-ray diffraction. All three complexes were found to exist as infinite one-dimensional (1-D) coordination polymers with the general formula {[Ln(L2)(3)(H(2)O)(2)]·xH(2)O}(n). Scrutiny of the packing diagrams for 2, 4, and 6 revealed the existence of interesting two-dimensional molecular arrays held together by intermolecular hydrogen-bonding interactions. Furthermore, the coordinated benzoate ligands serve as efficient light harvesting chromophores. In the cases of 1-4, the lowest energy maxima fall in the range 280-340 nm [molar absorption coefficient (ε) = (0.39-1.01) × 10(4) M(-1) cm(-1)]. Moreover, the Tb(3+) complexes 3 and 4 exhibit bright green luminescence efficiencies in the solid state (Φ(overall) = 60% for 3; 27% for 4) and possess longer excited state lifetimes than the other complexes (τ = 1.16 ms for 3; 1.38 ms for 4). In contrast to the foregoing, the Eu(3+) complexes 1 and 2 feature poor luminescence efficiencies.     

Synthesis of functional aromatic multisulfonyl chlorides and their masked precursors

The synthesis of functional aromatic bis(sulfonyl chlorides) containing an acetophenone and two sulfonyl chloride groups, i.e., 3,5-bis[4-(chlorosulfonyl)phenyl]-1-acetophenone (16), 3,5-bis(chlorosulfonyl)-1-acetophenone (17), and 3,5-bis(4-(chlorosulfonyl)phenyloxy)-1-acetophenone (18) via a sequence of reactions, involving in the last step the quantitative oxidative chlorination of S-(aryl)- N,N'-diethylthiocarbamate, alkyl- or benzyl thiophenyl groups as masked nonreactive precursors to sulfonyl chlorides is described. A related sequence of reactions was used for the synthesis of the aromatic trisulfonyl chloride 1,1,1-tris(4-chlorosulfonylphenyl)ethane (24). 4-(Chlorosulfonyl)phenoxyacetic acid, 2,2-bis[[[4-(chlorosulfonyl)phenoxyacetyl]oxy]methyl]-1,3-propanediyl ester (27), 5,11,17,23-tetrakis(chlorosulfonyl)-25,26,27,28-tetrakis(ethoxycarbonylmethoxy)calix[4]arene (38), 5,11,17,23,29,35-hexakis(chlorosulfonyl)-37,38,39,40,41,42-hexakis(ethoxycarbonylmethoxy)calix[6]arene (39), 5,11,17,23,29,35,41,47-octakis(chlorosulfonyl)-49,50,51,52,53,54,55,56-octakis(ethoxycarbonylmethoxy)calix[8]arene (40), 5,11,17,23-tetrakis(tert-butyl)-25,26,27,28-tetrakis(chlorosulfonyl phenoxyacetoxy)calix[4]arene (44), 5,11,17,23,29,35-hexakis(tert-butyl)-37,38,39,40,41,42-hexakis(chlorosulfonylphenoxyacetoxy)calix[6]arene (45), and 5,11,17,23,29,35,41,47-octakis(tert-butyl)-49,40,51,52,53,54,55,56-octakis(chlorosulfonylphenoxyacetoxy)calix[8]arene (46) were synthesized by two different multistep reaction procedures, the last step of both methods consisting of the chlorosulfonation of compounds containing suitable activated aromatic positions. 2,4,6-Tris(chlorosulfonyl)aniline (47) was obtained by the chlorosulfonation of aniline. The conformation of two series of multisulfonyl chlorides i.e., 38, 39, 40 and 44, 45, 46, was investigated by (1)H NMR spectroscopy. The masked nonreactive precursor states of the functional aromatic multisulfonyl chlorides and the aromatic multisulfonyl chlorides reported here represent the main starting building blocks required in a new synthetic strategy elaborated for the preparation of dendritic and other complex organic molecules.     

纤维素-[2,3-(4-取代苯基)-6-(3,5-二氯苯基)]氨基甲酸酯的合成及作为HPLC手性固定相的手性识别

合成了3种新的纤维素苯基氨基甲酸酯类衍生物:纤维素-[2,3-二苯基-6(3,5-二氯苯基)]氨基甲酸酯、纤维素-[2,3-二(4-甲基苯基)-6-(3,5-二氯苯基)]氨基甲酸酯及[2,3-二(4-氯苯基)-6-(3,5-二氯苯基)]氨基甲酸酯,并将其涂敷在氨丙基硅胶表面制备 HPLC 手性固定相.利用<'1>H N...     

Reactivities of novel [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes for alpha-tosyloxylation and alpha-phosphoryloxylation of ketones

Novel [hydroxy(tosyloxy)iodo]arenes bearing 2-thienyl, 3-thienyl, N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, and [hydroxy(phosphoryloxy)iodo]arenes bearing N-tosyl-4-pyrazolyl, 3-trifluoromethylphenyl, and 3,5-bis(trifluoromethy)phenyl as an aromatic group, were prepared. alpha-Tosyloxylation and alpha-phosphoryloxylation of ketones with these compounds were carried out, respectively. Their reactivities were compared with that of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene, respectively, and consequently [hydroxy(tosyloxy)iodo]arenes and [hydroxy(phosphoryloxy)iodo]arenes bearing 3-trifluoromethylphenyl and 3,5-bis(trifluoromethy)phenyl as an aromatic group showed the best reactivity. These new compounds can be used as powerful alpha-tosyloxylation and alpha-phosphoryloxylation reagents, instead of the parent [hydroxy(tosyloxy)iodo]benzene and [hydroxy(phosphoryloxy)iodo]benzene.     

Synthesis and mesomorphism behaviour of chalcones and pyrazoles type compounds as photo-luminescent materials

The following organic and organic–inorganic hybrid compounds were prepared as photo-luminescent materials following efficient and practical synthetic methods: 1,3-bis[4-(n-alkoxy)phenyl]-2-propen-1-one (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10); 3,5-bis[4-(n-alkoxy)phenyl]-1H-pyrazole (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10) (in case of n = 7, a mixture of 3,5-bis(4-heptyloxyphenyl)-1H-pyrazole and 3,5-bis(4-heptyloxyphenyl)-4H-pyrazole was detected) and bis(3,5-bis [4-(n-alkoxy) phenyl]-1H-pyrazole) silver(I) nitrate (where, n-alkoxy: O(CH₂)_nH, n = 6,7,8,9 or 10). The prepared compounds have been characterised and their structures were elucidated depending upon (FTIR, UV-Vis, ¹HNMR, ¹³CNMR, 2D ¹H-¹H-COSY, 2D ¹H-¹³C-HSQC and mass spectra) in addition to molar conductivity measurements for silver(I) complexes. The mesomorphism behaviour of the prepared compounds was studied using polarised light optical microscopy and confirmed with differential scanning calorimetry and X-ray powder diffraction techniques. The studies showed that among all of these compounds only the pyrazole derivatives are liquid crystal materials. The luminescent properties of all the prepared compounds were also investigated which confirmed that all of these compounds are photo-luminescent in the crystalline solid state and in the mesophase.     

Formation of substituted 6-hydroxy-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridine upon photochemical transformation of nifedipine

Long-term exposure of nifedipine to daylight in ethanol gives 2,2"-bis[3,5-bis(methoxycarbonyl)-2,6-dimethylpyridin-4-yl]azoxybenzene and 6-hydroxy-1-methoxycarbonyl-2,4-dimethyl-5-oxo-5,6-dihydrobenzo[c][2,7]naphthyridine as the major products.     

Initial investigation into the Suzuki-Miyaura vinylation of hindered aryl bromides utilizing potassium vinyltrifluoroborate

An initial study of the Suzuki-Miyaura cross-coupling of potassium vinyltrifluoroborate (2) and hindered aryl bromides is presented. Coupling of benzyl 3,5-bis(benzyloxy)-4-bromobenzoate (1) leads to a mixture of the desired styrene derivative, and the reduced product.     

Synthesis of 3,5-diaryl-4-chlorophthalates by [4+2] cycloaddition of 1-ethoxy-2-chloro-1,3-bis(trimethylsilyloxy)-1,3-diene with dimethyl acetylenedicarboxylate and subsequent site-selective Suzuki-Miyaura reactions

The [4+2] cycloaddition of 1-ethoxy-2-chloro-1,3-bis(trimethylsilyloxy)-1,3-diene with dimethyl acetylenedicarboxylate (DMAD) afforded dimethyl 4-chloro-3,5-dihydroxyphthalate. Site-selective Suzuki-Miyaura reactions of its bis(triflate) provide a convenient approach to 3,5-diaryl-4-chlorophthalates containing two different aryl groups.