- Preparation of acetals from aldehydes and alcohols under basic conditions
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A new, simple protocol for the synthesis of acetals under basic conditions from non-enolizable aldehydes and alcohols has been reported. Such reactivity is facilitated by a sodium alkoxide along with a corresponding trifluoroacetate ester, utilizing formation of sodium trifluoroacetate as a driving force for acetal formation. The usefulness of this protocol is demonstrated by its orthogonality with various acid-sensitive protecting groups and by good compatibility with functional groups, delivering synthetically useful acetals complementarily to the synthesis under acidic conditions from aldehydes and alcohols.
- Grabowski, Jakub,Granda, Jaros?aw M.,Jurczak, Janusz
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supporting information
p. 3114 - 3120
(2018/05/17)
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- Ortho-Phenylene bridged palladium bis-N-heterocyclic carbene complexes: Synthesis, structure and catalysis
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A series of ortho-phenylene bridged palladium bis-NHC complexes has been synthesized. Complexes with imidazolium and benzimidazolium derived NHCs and methyl-/benzyl-wingtips are reported. Bis(benz)imidazoles with a doubly brominated ortho-phenylene bridge could be obtained by an electrophilic substitution reaction. The structure of the complexes could be confirmed by three solid-state structures. All catalysts have been tested in the catalytic functionalisation of propane. The catalytic activity is highly dependent on the ligand, whereas ligand effects on the regioselectivity (n/iso) are much smaller.
- Munz, Dominik,Poethig, Alexander,Tronnier, Alexander,Strassner, Thomas
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p. 7297 - 7304
(2013/07/11)
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- Synthesis of 1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2.1]hept-5- enylmethyl haloacetates
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The possibility of preparing 1,4,5,6-tetrachloro-7,7-dimethoxybicyclo[2.2. 1]hept-5-enylmethyl haloacetates by the reaction of tetrachlorodimethoxycyclopentadiene with allyl haloacetates was examined. The effect of various factors on the product yield was studied, and the optimal synthesis conditions were found.
- Kyazymova,Mamedbeili,Abdiev,Nagiev,Alieva,Nagiev
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experimental part
p. 102 - 106
(2009/09/06)
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- Synthesis of bicyclo[2.2.1]hept-5-enyl methyl esters of haloacetic acids
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Synthesis of norbornenyl methyl esters of a number of haloacetic acids via [4+2] cycloaddition of cyclopentadiene to allyl esters of these acids was examined. The yield and isomer composition of the synthesized compounds were examined in relation to the reaction conditions, and the best conditions for their preparation were found.
- Kyazimova,Mamedbeili,Nagiev,Suleimanova,Khalilov
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experimental part
p. 1803 - 1807
(2009/09/08)
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- Competitive reactivity as a probe for reaction coordinates in gas-phase ion-molecule chemistry
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Using the method of competitive reactivity of two functional groups in the same molecule, anionic elimination reactions show considerable kinetic selectivity for small differences in leaving group thermochemistry, in structures of the general type YCH2CH2CH2Z, where Y and Z are good anionic leaving groups.
- Holman, Robert W.,Sumpter, Terry L.,Farrar, John,Weigel, Kurt,Bartmess, John E.
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p. 585 - 589
(2007/10/03)
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- TRIETHYL PHOSPHITE IN ORGANIC SYNTHESIS. A FACILE, ONE-POT CONVERSION OF ALCOHOLS INTO AMINES
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General protocols for converting primary, secondary, and tertiary alcohols into the corresponding primary amines are presented.
- Zwierzak, Andrzej
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- Energetic and Rate Effects of the Trifluoromethyl Group at C-2 and C-4 on the Aliphatic Claisen Rearrangement
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The rate of the Claisen rearrangement is accelerated by a factor of 73 over the parent system when a trifluoromethyl group is present at C-2 of allyl vinyl ether.Ground-state destabilization by the trifluoromethyl group may be responsible for this rate effect.There is little polar character in the transition state, and the transition-state structure has little carbonyl character and only moderate (ca. 1/3) bonding character between the two terminal carbons.The rate enhancement is not observed in the Cope rearrangement of the all-carbon analogue that has a trifluoromet hyl group at C-2.At C-4, the trifluoromethyl group does not bring about a significant rate effect in the Claisen rearrangement relative to the parent system; this result is in contrast to an energetic benefit of 3.5 kcal/mol enjoyed by the system when a cyano group is at C-4, which suggests that radical-stabilizing ability and not electronic-withdrawing ability is important in stabilizing the transition state.
- Gajewski, J. J.,Gee, K. R.,Jurayj, J.
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p. 1813 - 1822
(2007/10/02)
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- Anodic Oxidation of (Trimethylsilyl)methanes with ?-Electron Substituents in the Presence of Nucleophiles
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It was found that oxidation potentials of methanes with ?-electron substituents were decreased by introduction of a trimethylsilyl group.The anodic oxidation of benzyl-, allyl-, aryl(or alkyl)thiomethyl-, and aryloxymethyl-substituted trimethylsilanes smoothly proceeded in the presence of nucleophiles, e.g. alcohols and carboxylic acids, to eliminate the trimethylsilyl groups giving the corresponding alkoxylated and carboxylated products in moderate or high yields without full optimization of electrolytic conditions, while aminomethylsilanes did not undergo such a kind of anodic oxidation.
- Koizumi, Toshio,Fuchigami, Toshio,Nonaka, Tsutomu
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p. 219 - 225
(2007/10/02)
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- Regioselective Synthesis of Hydroxy Sulphides via Trifluoroacetoxysulphenylation of Derivatives of Allylic Alcohols
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Reaction of manganese(III) acetate with diphenyl disulphide in dichloromethane-trifluoroacetic acid in the presence of allylic esters gives trifluoroacetoxy sulphides, which on hydrolysis readily afford vicinal hydroxy sulphides.With acetate esters, neighbouring group participation by the acetate functionality controls the reaction course.Thus regiospecific addition to allyl acetate affords after hydrolysis only 3-phenylthiopropane-1,2-diol.In contrast, with trifluoroacetate esters the inductive effects of the trifluoroacetate functionality lead to a different regiocontrol.Thus addition of diphenyl disulphide to allyl trifluoroacetate gives after hydrolysis only 2-phenylthiopropane-1,3-diol.The regio- and stereochemistry of addition to a variety of other allylic (and homoallylic) esters is described and the extension of this type of regiocontrol is discussed.
- Samii, Zakaria K. M. Abd El,Ashmawy, Mohamed I. Al,Mellor, John M.
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p. 2509 - 2516
(2007/10/02)
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- REGIOSELECIVE HYDROXYSULPHENYLATION OF DERIVATIVES OF ALLYLIC ALCOHOLS AND AMINES
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Reaction of manganic acetate with diphenyldisulphide in dichloromethane-trifluoroacetic acid in the presence of allylic esters or amides of allylamine gives trifluoroacetoxysulphides and hence by ready hydrolysis vicinal hydroxysulphides.The regiochemical outcome can be controlled by selection of either an acetyl- or trifluoroacetyl derivative.
- Samii, Zakaria K M Abd El,Ashmawy, Mohamed I Al,Mellor, John M
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p. 5289 - 5292
(2007/10/02)
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