- Beryllium-Induced Conversion of Aldehydes
-
Aldehydes play a key role in the human metabolism. Therefore, it is essential to know their reactivity with beryllium compounds in order to assess its effects in the body. The reactivity of simple aldehydes towards beryllium halides (F, Cl, Br, I) was studied through solution and solid-state techniques and revealed distinctively different reactivities of the beryllium halides, with BeF2 being the least and BeI2 the most reactive. Rearrangement and aldol condensation reactions were observed and monitored by in situ NMR spectroscopy. Crystal structures of various compounds obtained by Be2+-catalyzed cyclization, rearrangement, and aldol addition reactions or ligation of beryllium halides have been determined, including unprecedented one-dimensional BeCl2 chains and the first structurally characterized example of an 1-iodo-alkoxide. Long-term studies showed that only aldehydes without a β-H can form stable beryllium complexes, whereas other aldehydes are oligo- and polymerized or decomposed by beryllium halides.
- Müller, Matthias,Buchner, Magnus R.
-
p. 11147 - 11156
(2019/08/12)
-
- A convenient approach for the synthesis of 1,3,5-trioxanes under solvent-free conditions at room temperature
-
A series of environmentally benign bis-SO3H-functionalized Bronsted acidic ionic liquids were synthesized by using aliphatic polyamines and 1,3-propanesultone as the source chemicals. These ionic liquids acted as efficient inexpensive and recyclable catalysts for cyclotrimerization of aliphatic aldehydes at room temperature under solvent-free conditions. The reactions proceeded smoothly with good to excellent isolated yields (66.9-97.6 %=) and were generally complete in 1.5 h when the amount of ionic liquids was 0.1 mol%. The ionic liquids could be recovered readily and reused five times without any significant loss in their catalytic activity. Graphical abstract: [Figure not available: see fulltext.]
- Li, Xinzhong,Lin, Qi,Cao, Rong
-
p. 1017 - 1022
(2014/06/09)
-
- Novel acidic ionic liquids as efficient and recyclable catalysts for the cyclotrimerization of aldehydes
-
A mild, efficient, and ecofriendly procedure for cyclotrimerization of aldehydes was realized by using a series of novel Brnsted acidic ionic liquids (BAILs) consisting of double-SO3H groups in cations as catalysts. Good conversion of aldehydes and selectivity of trialkyl-1,3,5-trioxanes were achieved by using 1mol% of BAILs. In addition, the catalyst system could be recycled and reused at least eight times without apparent loss of activity. Taylor & Francis Group, LLC.
- Song, Heyuan,Chen, Jing,Xia, Chungu,Li, Zhen
-
experimental part
p. 266 - 273
(2011/10/31)
-
- Tetranuclear BINOL-titanium complex in selective direct aldol additions
-
(Chemical Equation Presented) The extremely robust and water-stable tetranuclear complex Ti4(μ-BINOLato)6(μ3- OH)4 (1) catalyzes the direct aldol addition with high degrees of regioselectivity at the sterically more encumbered α-side of unsymmetrical ketones. The formation of quaternary stereocenters is described. Oxygen-containing ene components can also be used as starting material in these reactions. When used with aliphatic aldehydes, acetals 18 or acetals of aldol adducts 20 were observed. As few as 0.2 mol % loadings with this catalyst 1 were enough to complete the reactions. Mechanistical aspects of the reactions are discussed.
- Schetter, Bernd,Ziemer, Burkhard,Schnakenburg, Gregor,Mahrwald, Rainer
-
p. 813 - 819
(2008/09/18)
-
- InCl3 as an efficient catalyst for cyclotrimerization of aldehydes: Synthesis of 1,3,5-Trioxane under solvent-free conditions
-
1,3,5-Trioxanes derived from aldehydes were synthesized using indium trichloride as a catalyst. Cyclotrimerization of the aldehydes gave excellent yields under neat conditions within a short span of time. Copyright Taylor & Francis, Inc.
- Elamparuthi,Ramesh,Raghunathan
-
p. 2801 - 2804
(2007/10/03)
-
- Tandem reactions of Friedel-Crafts/aldehyde cyclotrimerization catalyzed by an organotungsten Lewis acid
-
The tris(2-pyridyl)phosphine complex [P(2-py)3 W(CO)(NO)2](BF4)2 acts as a Lewis acid catalyst precursor for the tandem reactions of Friedel-Crafts/aldehyde cyclotrimerization, which lead to the formation of a series of hyper-branched star polymers.
- Wang, Hsing-Shiun,Yu, Shuchun Joyce
-
p. 1051 - 1055
(2007/10/03)
-
- A convenient solvent-free preparation of 1,3,5-trioxanes
-
In the presence of a small amount of trimethylsilyl chloride, aldehydes gave at room temperature in solvent-free conditions the corresponding 1,3,5-trioxanes with good to excellent yields.
- Augé, Jacques,Gil, Richard
-
p. 7919 - 7920
(2007/10/03)
-
- Acetonyltriphenylphosphonium bromide in organic synthesis: A useful catalyst in the cyclotrimerization of aldehydes
-
Acetonyltriphenylphosphonium bromide (ATPB) is a useful catalyst for the cyclotrimerization of the aliphatic aldehydes under solvent-free condition. The aldehydes tethered with a variety of functionality such as olefin, ether, ester, bromide, azide and diester could also be cyclotrimerized under the catalysis of ATPB.
- Hon, Yung-Son,Lee, Chia-Fu
-
p. 6181 - 6188
(2007/10/03)
-
- Synthesis of 1,3,5-trioxanes: A new, simple method using a bentonitic earth as catalyst
-
A simple method for synthesizing aliphatic as well as aromatic 1,3,5-trioxanes using as catalyst a bentonitic earth is reported. The yields ranged from good to excellent.
- Camarena,Cano,Delgado,Zuniga,Alvarez,Garcia
-
p. 6857 - 6858
(2007/10/02)
-
- Cyclotrimerization of Aliphatic Aldehydes Catalysed by Keggin-type Heteropoly Acids and Concomitant Phase Separation
-
The acid-catalysed cyclotrimerization of aliphatic aldehydes has been examined through comparison of heteropoly acids with other acid catalysts.A Keggin-type heteropoly acid such as phosphomolybdic acid catalyses the cyclotrimerization of aldehydes, such as ethanal, propanal, butanal, 2-methylpropanal, 2,2-dimethylpropanal, hexanal, octanal, and decanal, to produce the respective 2,4,6-trialkyl-1,3,5-trioxanes in high yields.Catalysts turnover number of the heteropoly acid is more than 10000 for propanal cyclotrimerization.In addition to the high catalytic activities, the reaction mixture spontaneously separates into two phases, a produ ct phase and a catalyst phase, at high conversions of aldehyde.For propanal cycltrimerization, the reaction mixture separates into two liquid phases, and the recovered catalyst phase may be repeatedly applied to the reaction without additional care in isolation of the catalyst.The phase separation phenomenon has been concluded to be caused by the insolubility of the heteropoly acid coordinated with propanal in the product 2,4,6-triethyl-1,3,5-trioxane.
- Sato, Satoshi,Furuta, Hiromi,Sodesawa, Toshiaki,Nozaki, Fumio
-
p. 385 - 390
(2007/10/02)
-
- Reactions of Trimethylsilyl Isothiocyanate with Aldehydes and Acetals. Synthesis of Symmetrically and Unsymmetrically Isothiocyanato-Substituted Ethers
-
The reactions of trimethylsilyl isothiocyanate (TMSTC) with aldehydes catalyzed by Lewis acid gave α,α'-diisothiocyanato ethers in good to excellent yields.Similarly, unsymmetrical α-isothiocyanato ethers were obtained from the reactions of TMSTC with acetals in appropriate yieds.
- Nishiyama, Kozaburo,Oba, Makoto
-
p. 2289 - 2291
(2007/10/02)
-
- ALLYLSTANNATION. III. SYNTHESIS OF HOMOALLYLIC ALCOHOLS AND 4-CHLORO-2,6-DIALKYL-3-METHYLTETRAHYDROPYRANS BY REACTIONS BETWEEN (E/Z)-2-BUTENYLDICHLORO-n-BUTYLTIN AND ALDEHYDES
-
2-Butenyldichloro-n-butyltin (in various cis/trans isomer ratios) reacts readily with neat RCHO (R = CH3, C2H5, (CH3)2CH, and C6H5) at 25 deg C to give (a) linear alcohols, RCH(OH)CH2CH=CHCH3 in the E and Z forms, (b) branched alcohols, RCH(OH)CH(CH3)CH=CH2 in the threo and erythro forms, and (c) 2,3,4,6-tetrasubstituted tetrahydropyrans (A) as a mixture of cis/trans isomers arising from the CH(CH3)-CHCl bond.The maximum yields of these tetrahydropyrans were obtained by the use of 3-3.5 molar ratios RCHO/tin compound in the absence of solvents, whereas work-up after reactions in CH2Cl2 gave linear alcohols as the main products.The formation of linear alcohols appears to be stereospecific, as the ratio of E/Z isomers obtained is the same as that in the organotin compound.Tetrahydropyrans are formed preferentially as the trans isomers.
- Gambaro, Alessandro,Boaretto, Andrea,Marton, Daniele,Tagliavini, Giuseppe
-
p. 293 - 304
(2007/10/02)
-
- Process for the manufacture of cyclic acetals of aliphatic aldehydes
-
A process for preparing a cyclic acetal from a saturated, aliphatic aldehyde comprises contacting a saturated, aliphatic aldehyde of 2-16 carbon atoms with a silica gel.
- -
-
-
- THE REACTIONS OF DIPHENYLLITHIOARSINE AND DIPHENYLARSINE WITH ALDEHYDES
-
Diphenyllithioarsine reacts with aldehydes (RCHO, R=CH2CH3, CH(CH3)2, and Ph) to form lithium salts of α-hydroxyalkylarsines.Protonation of the lithium salts gives α-hydroxyalkylarsines.Diphenylarsine reacts with aldehydes below room temperature in the absence of solvents to produce white solids.The reactions are rapid in the presence of acid catalysts.Proton and carbon-13 NMR, infrared and Raman spectra show that the products are diphenyl-(α-hydroxyalkyl)arsines, Ph2AsCHOHR.These compounds are thermally unstable.In organic solvents, equilibrium is established between the α-hydroxyalkylarsines and the aldehyde and diphenylarsine.
- Busse, P. J.,Hrung, C-P.,Irgolic, K. J.,O'Brien, D. H.,Kolar, F. L.,Seoud, Omar A. El
-
-