110929-20-9

Upstream product

• 586-75-4 4-chlorobenzoyl chloride 
• 1122-91-4 4-bromo-benzaldehyde 
• 873-75-6 4-bromobenzenemethanol 
• 141-43-5 ethanolamine 
• 20614-06-6 bis(4-bromobenzyl) ether 
• 589-15-1 1-bromomethyl-4-bromobenzene 
• 106-38-7 para-bromotoluene 

Downstream Products

• 1566593-61-0 2-((4-bromobenzyl)oxy)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 

Relevant academic research and scientific papers

An environmentally benign solvent-free Tishchenko reaction

Herein, we describe the solvent-free ball milling Tishchenko reaction. Using high speed ball milling and a sodium hydride catalyst, the Tishchenko reaction was performed for aryl aldehydes in high yields in 0.5 hours. The reaction is not affected by the type of ball bearing used and can be successful when conducted in a liquid nitrogen environment.

Simple Syntheses, Structural Diversity, and Tishchenko Reaction Catalysis of Neutral Homoleptic Rare Earth(II or III) 3,5-Di-tert-butylpyrazolates - The Structures of [Sc(tBu2pz)3], [Ln2(tBu2pz)6] (Ln = La, Nd, Yb, Lu), and [Eu4(tB2pz)8]

The homoleptic rare-earth pyrazolate complexes [Sc(tBu2pz)3], [Ln2(tBu2pz)6] (Ln = La, Nd, Sm, Lu), [Eu4(tBu2pz)8] and the mixed oxidation state species [Yb2(tBu2pz)5] (tBu2pz = 3,5-di-tert-butylpyrazolate) have been prepared by a simple reaction between the corresponding rare-earth metal and 3,5-di-tert-butylpyrazole, in the presence of mercury, at elevated temperatures. In addition, [Yb2(tBu2pz)6] was prepared by redox transmetallation/ligand exchange between ytterbium, diphenylmercury(II) and tBu2pzH in toluene, whilst the same reactants in toluene under different conditions or in diethyl ether gave [Yb2(tBu2pz)5]. The complexes of the trivalent lanthanoids display dimeric structures [Ln2(tBu2pz)6] (Ln = La, Nd, Yb, Lu) with chelating η-terminal and η2:η2-bridging pyrazolate coordination. The considerably smaller Sc(3+) ion forms monomeric [Sc(tBu2pz)3] of putative D3h molecular symmetry, with pyrazolate ligands solely η2-bonded. [Eu4(tBu2pz)8] is a structurally remarkable tetranuclear Eu(II) complex with two types of europium centres in a linear array. The outer two are bonded to one terminal and two bridging pyrazolates, and the inner two are coordinated by four bridging ligands. Unprecedented μ-η5:η2 pyrazolate ligation is observed, with each outer Eu(2+) sandwiched between two η5-bonded pyrazolate groups, which are also η2-linked to an inner Eu(2+). The two inner Eu(2+) ions are linked together by two equally occupied components of each of two symmetry related, disordered pyrazolate groups with one component η4:η2 bridging and one η3:η2 bridging. [La2(tBu2pz)6] has also been shown to be a Tishchenko reaction catalyst with several organic substrates.

Heavier alkaline earth amides as catalysts for the Tischenko reaction

(Chemical Equation Presented) Homoleptic heavier alkaline earth amides, M{N(SiMe3)2}2(THF)2 (M = Ca, Sr, and Ba) are reported as precatalysts for the dimerization of aldehydes to the analogous carboxylic esters (Tischenko reaction).

The promoted Tishchenko reaction and catalytic intermediate by 2-aminopyrrolyl dilithium compounds

The dimerization of aldehydes to the analogous carboxylic esters (Tischenko reaction) has been achieved in impressive yields using the dilithium compounds containing bidentate di-anionic pyrrolyl ligands as initiators. The initiated intermediate {[2-(tBuNCH)C4H3NLi][PhCH2OLi(TMEDA)]}2 was isolated and characterized by satisfactory C, H and N microanalysis, 1H, 13C{1H} and 7Li NMR spectra in pyridine-d5 at ambient temperature, and single crystal X-ray structural data. The processes involve a redox reaction of 2-aminopyrrolyl dilithium compound with aldehyde.

Chemoselective and Metal-Free Synthesis of Aryl Esters from the Corresponding Benzylic Alcohols in Aqueous Medium Using TBHP/TBAI as an Efficient Catalytic System

A novel and transition-metal-free strategy has been developed for the synthesis of aryl esters starting from corresponding benzylic primary alcohols as the exclusive substrates using tert -butyl hydroperoxide (TBHP) as a terminal oxidant in the presence of catalytic amount of tetrabutylammonium iodide (TBAI) and imidazole, where the aliphatic alcohols remained unaffected. These reactions are highly chemoselective and associated with high yield and wide applicability accommodating a wide range of substituents. Excellent chemoselectivity has also been demonstrated through intramolecular competition experiments. This protocol can be considered as an important analogue of Tishchenko reaction using benzylic alcohols as the substrates instead of benzaldehydes.

Tishchenko reaction using an iridium-ligand bifunctional catalyst

Tishchenko reaction of aldehydes in the presence of an amino alcohol-based Ir bifunctional catalyst was developed. The reaction proceeds with 1 mol% of the catalyst and 20-30 mol% of K2CO3 in acetonitrile at room temperature to give the corresponding dimeric esters in good yield. Georg Thieme Verlag Stuttgart.

Polymeric ionic liquid and carbon black composite as a reusable supporting electrolyte: Modification of the electrode surface

One of the major impediments to using electroorganic synthesis is the need for large amounts of a supporting electrolyte to ensure the passage of charge. Frequently this causes separation and waste problems. To address these issues, a polymeric ionic liqu

Sodium hydride catalyzed Tishchenko reaction

A convenient and practical method for the dimerization of aldehydes is described. The conversion of aromatic and even heteroaromatic aldehydes in the presence of catalytic amounts of sodium hydride leads to the corresponding Tishchenko esters in high yields (up to 95 %). The reaction can be performed under standard laboratory conditions and on a multigram scale (up to 10 g). The use of catalytic amounts of sodiumhydride as an efficient promoter for the dimerization of aromatic and even heteroaromatic aldehydes under standard laboratory conditions is reported. A range of substituted aromatic and heteroaromatic aldehydes was converted, and the corresponding esters were obtained in good to excellent yields even on a multigram scale. Copyright

Aluminum complexes of β-hydroxy-imino ligands: Synthesis, structures and application in the Tishchenko reaction

Four aluminum alkoxide complexes containing β-hydroxy-imino ligands, [(2,6-Me2C6H3)NCPhCH2CPh2O]2AlMe (3a), [(2,6-iPr2C6H3)NCPhCH2CPh2O]2AlMe (3b), [(2,6-Me2C6H3)NCPhCH2C(C12H8)OAlMe2]2 (3c) and [(2,6-iPr2C6H3)NCPhCH2C(C12H8)OAlMe2]2 (3d) were synthesized in high yields, and their structural features were provided. The catalytic behavior of those four complexes about the Tishchenko reaction with a range of aromatic aldehydes as substrates were assessed, and it present a synthetically useful protocol to the solvent-free Tishchenko reaction under mild conditions.

Alkali metal tert-butoxides, hydrides and bis(trimethylsilyl)amides as efficient homogeneous catalysts for Claisen-Tishchenko reaction

Shelf-available alkali metal tert-butoxides, hydrides and bis(trimethylsilyl)amides were shown to be highly efficient homogeneous precatalysts for the disproportionation of aldehydes to the corresponding carboxylic esters. Potassium compounds in combination with 18-crown-6 ether could drastically increase the rate of reaction in a few cases. Alternatively, efficient aldol condensations were found for aldehydes possessing an enolizable methylene group at the α-position to the aldehyde functionality. The active species involved in this esterification using any of these alkali metal catalysts is expected to be the metal alkoxide. Potassium compounds were found to be much more efficient when compared to analogous sodium compounds and kinetic studies revealed the rate-determining step to be a second order concerted hydride transfer from a potassium hemiacetal species to another molecule of aldehyde. Copyright