- Bis-Pocket Porphyrins without meso-Substituents: Tetramethyltetra(2,4,6-triisopropylphenyl)porphyrin I and Tetrametyltetraterphenylporphyrin I
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A facile synthesis of meso-unsubstituted but doubly fenced porphyrins is described.The required pyrroles are made by the Barton-Zard method from 2,4,6-triisopropylbenzaldehyde and 2,6-diphenylbenzaldehyde.An X-ray structure confirms the type I pattern.
- Bag, Nilkamal,Chern, Shuenn-Shing,Peng, Shie-Ming,Chang, C. K.
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Read Online
- METHOD FOR PRODUCING CARBONYL COMPOUND
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PROBLEM TO BE SOLVED: To provide a method for producing a carbonyl compound, allowing for improvement of ease of production and furthermore allowing for reduction of production cost, by positively utilizing inexpensive iodine. SOLUTION: A carbonyl compound is produced by mixing primary alcohol or secondary alcohol, and iodic acid (HIO3) in a non-solvent or an aprotic polar solvent based on the following general formula (1), where R1 is an optionally substituted linear- or branched 1-12C aliphatic group, or an optionally substituted aromatic group; R2 is a hydrogen atom, an optionally substituted linear- or branched 1-12C alkyl group, or an optionally substituted aromatic group; R1 and R2 each may be coupled with each other to form a ring of aromatic group or a non-aromatic group. SELECTED DRAWING: None COPYRIGHT: (C)2018,JPOandINPIT
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Paragraph 0032-0035; 0037-0040
(2018/03/23)
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- Click-binol-phosphoric acid catalysts in intramolecular enantioselective oxidative C[sbnd]H-bond functionalization
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Counteranion-catalysis represents an appealing but challenging approach for the development of enantioselective oxidative C[sbnd]H bond functionalization reactions. In this work, a new family of 3,3′-triazolyl BINOL-derived phosphoric acids was synthesized and employed in the intramolecular asymmetric C[sbnd]H bond functionalization of N-aryl substituted tetrahydroisoquinolines. As previously reported with related structures, the presence of the triazole groups on the catalysts was key to attain enantioselectivity. Our study also shows the importance of choosing the appropriate regioisomeric triazole groups at the BINOL backbone to achieve a more efficient chirality transfer. Moderate enantiomeric ratios were obtained with the N-benzamide substrates, whereas the change of the nature of the nucleophile fragment was translated to a dramatic loss of the enantioselectivity. Therefore, it can be foreseen that there is a need for designing further superior catalyst structures to develop future counter-anion organocatalyzed asymmetric C[sbnd]H bond functionalization reactions.
- Stockerl, Sebastian,Gutiérrez, Daniel,García Manche?o, Olga
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p. 572 - 585
(2016/12/16)
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- Synthetic utility of iodic acid in the oxidation of benzylic alcohols to aromatic aldehydes and ketones
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Various primary and secondary benzylic alcohols were efficiently oxidized to aromatic aldehydes and aromatic ketones with iodic acid in DMF at 60?°C for 2?h and with iodic acid in the presence of TEMPO (5?mol?%) in DMF at room temperature, respectively. The former method was effective for the oxidation of sterically hindered alcohols at 60?°C and the latter method was effective for the oxidation of less sterically hindered alcohols at room temperature.
- Imai, Sho,Togo, Hideo
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p. 6948 - 6954
(2016/10/13)
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- Iminoborylene complexes: evaluation of synthetic routes towards BN-allenylidenes and unexpected reactivity towards carbodiimides
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The synthetic and reaction chemistries of cationic iminoborylene complexes [LnM=B=N=CR2]+, which feature a unique heterocumulene structure, have been systematically investigated. Precursors of the type CpFe(CO)2B(Cl)NCAr2 (Ar = p-Tol/Mes, 5c/d) have been generated by B-centred substitution chemistry using CpFe(CO)2BCl2 and suitable lithiated ketimines - a reaction which is found to be highly sensitive to the steric bulk at both the metal fragment and the ketimino group. Carbonyl/phosphine exchange (using PCy3 or PPh3), followed by halide abstraction allows for the generation of the cationic iminoborylenes [CpFe(PR3)(CO)(BNCAr2)]+[BArX 4]- (R = Cy, Ar = p-Tol/Mes, 12c/d; R = Ph, Ar = Mes, 13d; ArX = 3,5-X2C6H3 where X = Cl, CF3) which have been characterized spectroscopically and by X-ray crystallography. The reactivity of these iminoborylene systems towards a range of nucleophiles and unsaturated substrates has been investigated. The latter includes the first examples of M=B metathesis reactivity with a carbodiimide, and results in Fe=B cleavage and formation of the isonitrile complexes [CpFe(PCy3)(CO)(CNR)]+[BArCl 4]- (R = iPr/Cy, 16/17).
- Niemeyer,Kelly,Riddlestone,Vidovic,Aldridge
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supporting information
p. 11294 - 11305
(2015/06/25)
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- A direct and mild formylation method for substituted benzenes utilizing dichloromethyl methyl ether-silver trifluoromethanesulfonate
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A silver trifluoromethanesulfonate (AgOTf)-promoted direct and mild formylation of benzenes has been developed. The reaction utilizing dichloromethyl methyl ether (Cl2CHOMe) and AgOTf powerfully formylated various substituted benzenes under temperature conditions as low as -78 C without losing the protecting groups on the phenolic hydroxyl group.
- Ohsawa, Kosuke,Yoshida, Masahito,Doi, Takayuki
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p. 3438 - 3444
(2013/06/26)
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- Substrate range of the titanium TADDOLate catalyzed asymmetric fluorination of activated carbonyl compounds
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The substrate range of the [TiCl2(TADDOLate)] (TADDOL=α,α,α′,α′-tetraaryl-1,3-dioxolane-4, 5-dimethanol)-catalyzed asymmetric α-fluorination of activated β-carbonyl compounds has been investigated. Optimal conditions for catalysis are characterized by using 5 mol-% of TiCl2(naphthalen-1- yl)-TADDOLate) as catalyst in a saturated (0.14 mol/l) MeCN solution of F-TEDA (1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane bis- [tetrafluoroborate]) at room temperature. A series of α-methylated β-keto esters (3-oxobutanoates, 3-oxopentanoates) with bulky benzyl ester groups (60-90% ee) or phenyl ester (67-88% ee) have been fluorinated readily, whereas α-acyl lactones were also readily fluorinated, but gave lower inductions (13-46% ee). Double stereochemical differentiation in β-keto esters with chiral ester groups raised the stereoselectivity to a diastereomeric ratio (dr) of up to 96.5:3.5. For the first time, β-keto S-thioesters were asymmetrically fluorinated (62-91.5% ee) and chlorinated (83% ee). Lower inductions were observed in fluorinations of 1,3-diketones (up to 40% ee) and β-keto amides (up to 59% ee). General strategies for preparing activated β-carbonyl compounds as important model substrates for asymmetric catalytic α-functionalizations are presented (>60 examples). Copyright
- Bertogg, Andreas,Hintermann, Lukas,Huber, Dominique P.,Perseghini, Mauro,Sanna, Maria,Togni, Antonio
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body text
p. 353 - 403
(2012/05/07)
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- Synthesis and reactivity of an unprecedented osmium(VIII) alkylidene
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The synthesis of a family of Os(VIII) alkylidene complexes, the highest oxidation state alkylidenes known to date, and their reactivity toward small organic molecules are reported.
- Martin, Véronique,Blakey, Simon
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scheme or table
p. 6800 - 6803
(2009/04/06)
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- Correlated rotations in benzylfluorene derivatives: Structure, conformation, and stereodynamics
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(Graph Presented) Fluorene derivatives, having substituted benzyl groups bonded to position 9, have been investigated by variable temperature NMR spectroscopy. Stereodynamic processes involving restricted rotation about the fluorenyl-CH2 and ar
- Casarini, Daniele,Lunazzi, Lodovico,Mazzanti, Andrea
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p. 2811 - 2818
(2008/09/19)
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- Generation and detection of a relatively persistent carboxylic acid enol-2,2-bis(2′,4′,6′-triisopropylphenyl)ethene-1,1-diol
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Ditipyl ketene (tipyl = 2,4,6-triisopropylphenyl) (20), ditipylacetic acid (19), and 2,2-ditipyl bis-(trimethylsilyl) acetal 28 were prepared as potential precursors for the enol of 19, i.e., 2,2-ditipylethene-l,l-diol (25). Protonation of the dianion of
- Frey, Joseph,Rappoport, Zvi
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p. 5169 - 5181
(2007/10/03)
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- Generation and conversion of the transient 1,1-bis(trimethylsilyl)-2-(2,4,6-triisopropylphenyl)-silene
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Treatment of 2,4,6-triisopropylbenzaldehyde with tris(trimethylsilyl)silylmagnesium bromide (2) gives 2,4,6-triisopropylphenyl-tris(trimethylsilyl)silyl-methanol (3) in approximately 70% yield and E-3,4-bis(2,4,6-triisopropylphenyl)-1,1,2,2-tetrakis(trimethylsilyl)-l,2-disilacyclobutane (5) (15%). 5 is the [2 + 2] head-to-head cyclodimer of the transient 1,1-bis(trimethylsilyl)-2-(2,4,6-triisopropylphenyl)-silene (4), formed by trimethylsilanolate elimination according to a Peterson mechanism from the magnesium alkoxide, derived from the alcohol 3. Deprotonation of 3 with MeLi at low temperature in ether produces a complex mixture of products, the main constituents being the silene dimer 5 (10%) and bis(trimethylsilyl)-2,4,6-triisopropylbenzyl-trimethylsiloxysilane (10) (60%), which is formed by readdition of the eliminated lithiumtrimethylsilanolate at the Si=C bond of 4. The deprotonation of 3 with MeMgBr or PhMgBr (activated by LiBr) in THF at room temperature results in the formation of the polysilane (Me3Si)3SiSi(SiM3)2CH2(2,4,6-C6H2iPr3) (13). Its generation indicates that there exists an equilibrium between the magnesium alkoxide derived from the alcohol 3 on one side, and the magnesium silanide 2 and 2,4,6-triisopropylbenzaldehyde on the other side. Possible pathways of the formation of the compounds mentioned, as well as of further by-products, are discussed. The 1,2-disilacyclobutane 5 is characterized by an X-ray crystal structure analysis.
- Luderer, Frank,Reinke, Helmut,Oehme, Hartmut
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p. 181 - 188
(2007/10/03)
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- Formation and reactivity of (tetraarylporphyrinato)rhodium(II) monocarbonyls: Bent RhIICO complexes that react like acyl radicals
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Reactions for a series of rhodium(II) porphyrins with CO are used in illustrating the use of ligand steric effects in both promoting and inhibiting CO coupling to form α-diketone complexes ((por)RhC(O)C(O)Rh(por)). [Tetrakis(2,4,6-trimethylphenyl)porphyri
- Wayland, Bradford B.,Sherry, Alan E.,Poszmik, George,Bunn, Andrew G.
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p. 1673 - 1681
(2007/10/02)
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- Process for the preparation of substituted benzaldehydes
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Substituted benzaldehydes are prepared by reaction of the substituted benzenes from which they are derived with carbon monoxide and hydrogen chloride in the presence of metal halides, the process being performed in the presence of 0.5 to 10 mols of hydrogen chloride per mol of metal halide at a partial pressure of carbon monoxide from 1 to 100 bars and a temperature from -20° C. to +100° C. and, if desired, in the presence of an inert diluent. The substituted benzaldehyde which contains, as a substituent, alkyl with at least 2 carbon atoms, cycloalkyl or optionally substituted benzyl, is prepared by reacting the appropriately substituted benzene with the additional presence of a benzene which does not contain the substituents mentioned, but which is identical in respect of further substituents which are optionally present with the benzene from which it is derived.
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- 1,3,5-Trineopentylbenzene and Related 1,3,5-Trialkylbenzenes Containing Groups with Both Steric and Conjugative Effects. 1H NMR Band Shape and 13C Spin Lattice Relaxation Time Measurements and Force Field Calculations
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2,4,6-Trialkylsubstituted styrenes, benzaldehydes and N-methylbenzaldimines were studied by the 1H NMR band shape and 13C spin lattice relaxation time techniques.The results were in most cases found to be well reproduced by molecular mechanics calculations with the Allinger MMP1 and MMP2 programs.In the case of 2,4,6-trineopentylstyrenes, it was found that a cis-β-vinylic methyl group is responsible for the high barrier to internal rotation (74 kJ mol-1) observed.The compound with a trans-β-vinylic methyl group has a barrier (-1), of similar magnitude to that of 2,4,6-trineopentylstyrene itself.For the benzaldehydes and N-methylbenzaldimines, an upper limit to the barrier of -1 in all cases was estimated by 13C spin lattice relaxation time measurements.A model involving free diffusion in a restricted range was used to calculate internal correlation times from T1 data.The influence of librational motions on rotational barriers from spin lattice relaxation time measurements is discussed.
- Anderson, Sven,Carter, Robert E.,Drakenberg, Torbjoern
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p. 579 - 596
(2007/10/02)
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