Reaction Of Aliphatic Ketones Research Articles

An investigation of chiral diamides as organocatalysts in asymmetric aldol reaction

AbstractSeven novel proline and 1,2,3,4‐tetrahydroisoquinoline‐3‐carboxylic acid (THIQA) based diamides were synthesized successfully by simple amidation reactions and characterized by their spectral data. Their catalytic activities in asymmetric aldol reaction were performed by the reactions of aliphatic ketones and various aromatic aldehydes. Especially, (S)‐N‐((S)‐1‐(morpholinoamino)‐1‐oxo‐3‐phenylpropan‐2‐yl)pyrrolidine‐2‐carboxamide (9e) showed good catalytic activities in water at room temperature in the presence of benzoic acid cocatalyst. The enantioselectivities were upto 89.6%, the diastereomeric ratios were upto 92/8, and yields were upto 97.3%. This catalyst showed its best catalytic activities in water; this is also an important contribution to green chemistry requirements.

Synthesis of New Di- and Triamides as Potential Organocatalysts for Asymmetric Aldol Reaction in Water

New di- or triamide organocatalysts derived from (L)-proline were synthesized and successfully used in the direct asymmetric aldol reaction of aliphatic ketones and aromatic aldehydes in water at 0oC in the presence of benzoic acid as co-catalyst. (S)-methyl-2-((S)-3-hydroxy-2-((S)-3-pyrrolidine-2-carboxamido)propanamido)-3-phenylpropanoate (7c) as organocatalyst showed best results under these reaction conditions, and good diastereoselectivities (up to 99%), enantioselectivities (up to 98%) and yields (up to 91%) were observed.

New and effective proline-based catalysts for asymmetric aldol reaction in water

ABSTRACTNew proline diamide organocatalysts with Pro-Phe peptide bonds were synthesized and their catalytic activities in asymmetric direct aldol reactions of aliphatic ketones with aromatic aldehydes were investigated. Catalyst 6a showed good enantioselectivity at 0 °C in the presence of p-nitrobenzoic acid as cocatalyst in water.

前周期低原子価ニオブ化合物の有機変換反応への利用 —量論反応から触媒反応へ—

This review consists mainly of stoichiometric reaction and catalytic reaction using niobium complexes. As an example of stoichiometric reaction, synthesis of 1H-indenes from the reaction of aliphatic ketones and aryl-substituted alkynes in the presence of stoichiometric amount of NbCl3(DME) has been documented. Alternatively, development of catalytic reaction of using low-valent Nb is intriguing. Our research group reported that low-valent Nb catalyzed intermolecular [2+2+2] cycloaddition reaction of alkynes with alkenes leading to tri- or tetra-substituted 1,3-cyclohexadienes in chemo- and regioselectivity. In addition, low-valent Nb catalyzed cycloaddition reaction of tert-butylacetylene with aryl-substituted nitriles to tri-substituted pyridines has been reported.

Diallylation of 2,2-dialkylbenzodioxoles from TiCl 4-mediated allylsilane reaction

Reaction of aliphatic ketones with catechol afforded 2,2-dialkylbenzodioxoles. Treatment of these benzodioxoles with allyltrimethylsilane in the presence of titanium tetrachloride led to 4,4-dialkylhepta-1,6-dienes resulting from a diallylation process. Ring-closing metathesis gave rise to 4,4-dialkylcyclopentenes.

Prolinamides versus Prolinethioamides as Recyclable Catalysts in the Enantioselective Solvent‐Free Inter‐ and Intramolecular Aldol Reactions

AbstractA solvent‐free asymmetric and direct anti‐aldol reaction of aliphatic ketones with aromatic aldehydes catalyzed by recyclable L‐prolineamides and L‐prolinethioamides 3 is studied. The L‐prolinethioamide 3d (5 mol%), derived from L‐Pro and (R)‐1‐aminoindane, is the most efficient catalyst for this process affording the anti‐aldol adducts in high yields with excellent diastereo‐ and enantioselectivities (up to >98/2 dr, up to 98% ee) at 0 °C or room temperature. Prolinethioamide 3d is an effective organocatalyst for the first asymmetric, solvent‐free, intramolecular Hajos–Parrish–Eder–Sauer–Wiechert reaction with comparable or higher levels of enantioselectivity (up to 88% ee) to reported catalysts in organic solvents. Moreover, organocatalyst 3d can be easily recovered and reused by a simple acid/base extraction.

Organocatalytic Asymmetric syn‐Aldol Reactions of Aldehydes with Long‐Chain Aliphatic Ketones on Water and with Dihydroxyacetone in Organic Solvents

AbstractAn on‐water, asymmetric, and direct syn‐aldol reaction of aliphatic ketones with aromatic aldehydes catalyzed by a primary amino acid‐based organocatalyst afforded the syn‐aldol adducts in high yields with excellent diastereo‐ and enantioselectivities (up to > 20/1 dr, >99% ee), and a highly enantioselective syn‐aldol reaction of dihydroxyacetone with a variety of aldehydes in THF proceeded with 14/1 to >20/1 dr and 92 to >99% ee. Water not only accelerated the reaction, but also enhanced the enantioselectivity. This positive water effect might arise from the hydrogen bond formed between a pendant hydroxy group of surface water molecules at the hydrophobic interface with the amide oxygen of the organocatalyst, which increases the acidity of the amide NH and thereby strengthens the related hydrogen bond formed with the aldehyde.

Low‐Valent Nb(III)‐Mediated Synthesis of 1,1,2‐Trisubstituted‐1H‐indenes from Aliphatic Ketones and Aryl‐Substituted Alkynes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Low-valent Nb(iii)-mediated synthesis of 1,1,2-trisubstituted-1H-indenes from aliphatic ketones and aryl-substituted alkynes

A variety of 1,1,2-trisubstituted-1H-indenes are synthesized by the reaction of aliphatic ketones, aryl-substituted alkynes and NbCl3(DME) in 1,2-dichloroethane under reflux conditions.

Regioselectivity in the Reaction of Aliphatic Ketones and Aromatic Nitriles. Regiospecific Synthesis of Alkylarylpyrimidines.

AbstractFor Abstract see ChemInform Abstract in Full Text.

On the regioselectivity in the reaction of aliphatic ketones and aromatic nitriles. Regiospecific synthesis of alkylarylpyrimidines

The reaction of aliphatic ketones with aliphatic or aromatic nitriles in the presence of trifluoromethanesulfonic anhydride has been shown to be a very useful method for the preparation of alkyl- and aryl-pirimidines. The reaction shows a high degree of regioselectivity that depends on the characteristics of the residues attached at the carbonyl group. The results from different branched symmetric and asymmetric ketones are shown. Molecular mechanics calculations permit an explanation and predict the results obtained. Regiospecific synthesis of alkyl aryl pyrimidines is described.

Synthesis of aliphatic thiomorpholides by willgerodt-kindler reaction under solvent-free conditions

The Willgerodt-Kindler reaction of aliphatic ketones and aldehydes with sulfur and morpholine under solvent-free conditions was performed in a domestic microwave oven. The method is simple, rapid and avoids prolonged heating with solvents.

A new preparation of methylenecyclopropanes utilizing trimethylsilyldiazomethane

Reactions of aliphatic ketones with lithium trimethylsilyl-diazomethane in the presence of excess olefins afforded methylenecyclopropanes in moderate to good yields. The multiplicity of the alkylidene carbene intermediate in the reacting state has been revealed to be a singlet.

Reactions of organic compounds with SF 4HF, SF 4HFCl 2(Br 2) and SF 4HFS 2Cl 2 systems

Until recently the reactions of sulfur tetrafluoride with organic compounds proceeding with the substitution of hydrogen atom by fluorine have been considered anomalous. An important achievement in sulfur tetrafluoride chemistry, substantially expanding its preparative utility, is the modification of its reactions by using new fluorinating systems, such as SF 4HF, SF 4HFCl 2(Br 2) and SF 4HFS 2Cl 2. We have found SF 4HFX 2 systems are effective in halofluorination and fluorination of various organic compounds in high yields. Results and mechanisms of reactions of alkanes, alkenes, ketones, linear and cyclic esters, heterocyclic compounds with SF 4HFX 2 systems will be discussed. Reactions of aliphatic ketones, alkenes and perfluoralkenes with SF 4HFS 2Cl 2 systems are proposed as a new general convenient route to fluorinated and perfluorinated sulfides, polysulfides and sulfochlorides.

Reaction of Aliphatic Ketones with α-Cyano-α, β-unsaturated Acid Derivatives

Abstract The reaction of several aliphatic ketones with α-cyano-α, β-unsaturated acid derivatives has been studied. Ethylidenecyanoacetic acid reacted with a large excess of acetone in an autoclave at 150–160°C to give 3-methyl-5-oxohexanonitrile, which was considered to be produced by the decarboxylation of the Michael-type adduct of acetone onto the acid. Similar adducts were obtained by the reaction of the acid with methyl ethyl ketone, cyclohexanone, and ethyl laevulinate. The reaction of ketones with ethyl ethylidenecyanoacetate did not afford Knövenagel-type condensates, but Michael-type adducts in appreciable yields, for example, ethyl 2-cyano-3,4-dimethyl-5-oxohexanoate from methyl ethyl ketone. Diethyl ethylidenemalonate also gave Michael-type adducts. These results seem to suggest that the γ-methyl group of ethylidenecyanoacetic acid or its ester is not active enough to give Knövenagel-type condensates with aliphatic ketones, and that, therefore, the Knövenagel-type reaction is preceded by the Michael-type addition reaction of ketones onto the activated carbon-carbon double bond.