Tischenko reaction

It is interesting to note that under the influence of aluminium alkoxides (in alcohol or, better, in benzene solution) aldehydes produce the ester (Tischenko reaction) ... 

Ethyl acetate [141-78-6] is produced commercially by the Tischenko condensation of acetaldehyde using an aluminum ethoxide catalyst (60). The Tischenko reaction of acetaldehyde with isobutyraldehyde [78-84-2] yields a mixture of ethyl acetate, isobutyl acetate [110-19-0] and isobutyl isobutyrate [97-85-8] (61). 

The Tischenko reaction is a related transformation where the product is an ester. 

Formaldehyde is readily reduced to methanol by hydrogen over many metal and metal oxide catalysts. It is oxidized to formic acid or carbon dioxide and water. The Cannizzaro reaction gives formic acid and methanol. Similarly, a vapor-phase Tischenko reaction is catalyzed by copper (34) and boric acid (38) to produce methyl formate ... 

The vapor-phase esterification of ethanol has also been studied extensively (363,364), but it is not used commercially. The reaction can be catalyzed by siUca gel (365,366), thoria on siUca or alumina (367), zirconium dioxide (368), and by xerogels and aerogels (369). Above 300°C the dehydration of ethanol becomes appreciable. Ethyl acetate can also be produced from acetaldehyde by the Tischenko reaction (370—372) using an aluminum alkoxide catalyst and, with some difficulty, by the boron trifluoride-catalyzed direct esterification of ethylene with organic acids (373). 

Citrinine la 69,147,148 Citronellal la 158,159 CitroneUol la 68-70,327 Citronellyl acetate la 68 Claisen-Tischenko reaction 15 54 Clathrate complex 15 303 Clavin alkaloids 15 243 Clavine alkaloids 15 246,252 Cleanup la 119 Clemastin 15 354 Clenbuterol 15 106,107,354 Clobutinol 15 354 Cloforex 15 194,296 Clomethiazole lb 354 Clomipramine 15 352,354,355 Clonacillin lb 301 Clonidine 15 354 Clopamide 15 354 Clorexolon 15321 Clotrimazol 15 98,99,401,402 Cloxacillin 1584,188 Clozapin 15 354 Cnicin 15 290... 

Ethyl acetate is an oxygenated solvent widely used in the inks, pharmaceuticals and fragrance sectors. The current global capacity for ethyl acetate is 1.2 million tonnes per annum. BP Chemicals is the world s largest producer of ethyl acetate. Conventional methods for the production of ethyl acetate are either via the liquid phase esterification of acetic acid and ethanol or by the coupling of acetaldehyde also known as the Tischenko reaction. Both of these processes require environmentally unfriendly catalysts (e.g. p-toluenesulphonic acid for the esterification and metal chlorides and strong bases for the Tischenko route). In 1997 BP Chemicals disclosed a new route to produce ethyl acetate directly from the reaction of ethylene with acetic acid using supported heteropoly acids... 

Steps including hydroxy directed diastereoselective Tischenko reaction... 

The dimer aldol (6) can then react further to form trimers (7, 8) either by acetal formation, Eq. (23), or by Tischenko reaction, Eq. (24). 

Tischenko reaction org chem The formation of an ester by the condensation of two molecules of aldehyde utilizing a catalyst of aluminum alkoxides in the presence of a halide. ti shag-ko re.ak shan j... 

Commercial acrolein (Shell Chemical Corp.) was distilled and shaken with an equal volume of anhydrous calcium sulfate for 30 minutes. The acrolein (containing an impurity of 3.5% of propionaldehyde) was distilled again just before use (b.p., 52.5—52.9° C.). Oxidation products identified using acrolein (99.9% purity) without propionaldehyde, which was removed by the Tischenko reaction (31). Solvents were used after purification (especially dehydration) by conventional methods. 

The Evans-Tischenko Reaction generally requires a P-hydroxyketone (developed from an Aldol reaction) to react with an aldehyde. The resulting glycol monoester will be characterized as having high anti-selectivity. 

An Aldol-Tischenko reaction is sometimes observed as a byproduct of Aldol condensation-. 

Thoria catalyst, 735 Tischenko reactions, 318 Tollen s ammoniacal silver nitrate reagent, 330, 1061, 1074 p-Tolualdehyde, 689, 697 o-Toluamide, 798 Toluene, 510, 516, 615 purification of, 173, 174 separation from benzene, 231 p-Toluenesulphinic acid, 821, 826 o-Toluenesulphonamide, 821, 824 p-Toluenesulphonamide, 820, 823 p-Toluenesulphonates, 422, 437, 650, 684 ... 

Diethylzinc was used as a catalyst for the preparation of polyesters from terephthalaldehyde via the Tischenko reaction (480), and for the polycondensation of ethylene glycol with dimethyl terephthalates to afford polyethylene terephthalate (340). Benzylzinc chloride has been used as a catalyst for polycondensation of benzyl chloride (223). 

Mlynarski J. Direct asymmetric aldol-Tischenko reaction. Fur. J. Org. Chem. 2006 4779 786. 

Boric acid catalyzes the self-condensation of aldehydes and ketones to produce a,/l-unsaturated enones [6]. The yields are much higher than those reported with other acidic or basic catalysts. Under similar conditions, aldehydes which are not readily susceptible to aldol condensation, dismutate to form esters (Tischenko reaction) [7]. A catalytic amount of boric acid-sulfuric acid mixture has been used to synthesize aryl esters in good yields (Eq. 3) [8] this reaction was unsuccessful when mineral acids or boric acid alone were used. 

Cross aldol reaction between two different aldehydes and/or ketones without prior activation or protection should provide a straightforward methodology for the synthesis of aldols, Mahrwald recently reported that treatment of aldehydes with TiCU and NEta (or TMEDA) gives rise to syn- do reaction in good yields (Eqs 38 and 39) [141], This method was extended to the aldehyde-ketone cross aldol reaction catalyzed by TiCU [142], an advantage of which is that reaction occurs at the more encumbered a-position of unsymmetrical ketones, as illustrated in Eqs (40) and (41) [143], The use of aliphatic aldehydes instead of PhCHO usually reduced stereoselectivity. When TiCU was replaced by a catalytic amount of BuTi(0-/-Pr)4Li, the aldol reaction was followed by the Tischenko reaction [144], Methyl vinyl ketone trimerized to give a chlorinated cyclic product with TiCU [145],... 

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