93-54-9Relevant academic research and scientific papers
A new heterometallic coordination polymer: Synthesis, structure, and catalytic property
Liu, Qi-Feng,Liu, Wei,Cao, Yi-Po,Dong, Yan-Li,Liu, Hui-Min
, p. 153 - 157 (2017)
A new heterometallic-organic framework, namely [CuCa(tdc)2(DMF)]n(1 H2tdc = 2,5-thiophenedicarboxylic acid, DMF = N,N’-dimethylformamide), has been successfully obtained through the solvothermal reactions of CuCl2, Ca(NO3)2, and H2tdc. Single-crystal structural analysis reveals that compound 1 features a 3D framework with the irl topology. Compound 1 has potential unsaturated metal sites after the removal of the coordinated DMF molecules, so it exhibits excellent catalytic activity for the diethylzinc addition to benzaldehyde.
Second-generation N,O-[2.2]paracyclophane ketimine ligands for the alkenylzinc addition to aliphatic and aromatic aldehydes: Scope and limitations
Lauterwasser, Frank,Gall, Julia,Hoefener, Sebastian,Braese, Stefan
, p. 2068 - 2074 (2006)
Second generation N,O-[2.2]paracyclophane ketimine ligands were investigated for their ability to catalyze the 1,2-addition of alkenyl-zinc reagents to aliphatic and aromatic aldehydes with special focus on functionalized substrates. For aliphatic aldehydes, which have always been challenging in this field, remarkably high enantiomeric excesses could be determined (50-95% ee). However, alkenylzinc reagents bearing heteroatoms proved to be demanding substrates for this system.
Kinetic investigations of product inhibition in the amino alcohol-catalyzed asymmetric alkylation of benzaldehyde with diethylzinc
Rosner, Thorsten,Sears, Patrick J.,Nugent, William A.,Blackmond, Donna G.
, p. 2511 - 2513 (2000)
(equation presented) In situ reaction rate measurements help to define the role of product inhibition in the asymmetric alkylation of benzaldehyde with diethylzinc using (-)-MIB as a chiral reagent. Reaction calorimetry and kinetic modeling demonstrated that the rate behavior over consecutive reactions may only be rationalized when reversible binding of the product alkoxide is taken into consideration. These results may have implications for the conversion dependence of product enantioselctivity in reactions using enantioimpure catalysts.
A chiral tetrahedral framework with tetrahedral guests for catalysis and photoluminescence
Chen, Yan-Fei,Ma, Yun-Cui,Chen, Shu-Mei
, p. 4154 - 4157 (2013)
Presented here is a chiral three-dimensional indium(III)-organic compound [In(5-Aip)2]·(TPP)·4H2O (1; 5-Aip = 5-aminoisophthalate, TPP = tetraphenylphosphonium). The structure of 1 features an unusual tetrahedral anionic framework containing tetrahedral TPP guests. This compound shows interesting photoluminescent properties and notable catalytic activity on the diethylzinc addition to benzaldehyde. The results reveal that the employment of tetrahedral TPP cations as guests can not only direct the formation of a tetrahedral framework but also help on the improvement of physical properties.
RZnI vs. R2Zn in Pd(0)-catalyzed cross-coupling reactions with thioimidates
Roberts, William P.,Ghosh, Indranath,Jacobi, Peter A.
, p. 279 - 284 (2004)
Thioimidates 1-Z undergo facile cross-coupling with Pd(0)-RZnI but are inert to Pd(0)-R2Zn. This difference is due to the lower Lewis acidity of R2Zn, as opposed to lower nucleophilicity. Various sources of RZnI (R = Me, Et) and Pd(0) were evaluated for their convenience and reactivity.
Stereoselective synthesis and transformations of pinane-based 1,3-diaminoalcohols
Gonda, Tímea,Balázs, Attila,Tóth, Gábor,Fül?p, Ferenc,Szakonyi, Zsolt
, p. 2638 - 2648 (2017)
A library of pinane-based 1,3-diaminoalcohols and 5-aminomethyloxazolidin-2-ones was developed from commercially available (1R)-(?)-myrtenol which was transformed to N-trichloroacetyl protected allyl amine via Overmann rearrangement followed by stereoselective epoxidation with mCPBA resulting in key intermedier epoxy-amine. In order to obtain the diaminoalcohol moiety, aminolysis and azidolysis of the oxirane ring was performed. The cleavage of the oxirane ring proceeded regioselectively, affording N-trichloroacetyl protected 1,3-diaminoalcohols and oxazolidin-2-ones, which were obtained also via a thermal cyclisation. Since N deprotection of diaminoalcohols was unsuccessful under varied conditions, the protecting group was changed and Boc-protected analogues were synthesised. In this case, removal of the Boc protecting group was successful resulting in the planned diamino alcohols. An unexpected extreme δ Meα-9 value (0.11?ppm) was measured for the dibenzylaminomethyl-substituted oxazolidine-2-one, and the stereostructure was refined by means of DFT geometry optimization. The obtained potential catalysts were applied in the test reaction of benzaldehyde and diethylzinc with low to moderate enantioselectivities (up to 74% ee).
A novel approach to conformationally strained 2,2′-bipyridine thiacrown ethers and their chiral sulfoxides by sequential homo-coupling/DA-rDA reaction of 5,5′-bi-1,2,4-triazine-containing thiamacrocycles
?awecka, Justyna,Karczmarzyk, Zbigniew,Wolińska, Ewa,Olender, Ewa,Branowska, Danuta,Rykowski, Andrzej
, p. 3098 - 3104 (2011)
The synthesis of conformationally strained 2,2′-bipyridine thiamacrocycles 5, 6, 9, 10 and their chiral sulfoxides 11-14 is elaborated using, (1) homo-coupling of 1,2,4-triazine sulfide 3 with potassium cyanide and (2) Diels-Alder/retro Diels-Alder (DA-rDA) with 2,5-norbornadiene or 1-pyrrolidino-1-cyclopentene as the key steps. The crystal structure determinations of 4-6 and the theoretical calculations at DFT/B3LYP/6-311 G level were conducted thus establishing conformational preferences of the target thiamacrocycles
Regio- and Stereoselective Synthesis of Bicyclic Limonene-Based Chiral Aminodiols and Spirooxazolidines
Le, Tam Minh,Csámpai, Antal,Fül?p, Ferenc,Szakonyi, Zsolt
, p. 13607 - 13615 (2018)
A library of monoterpene-based aminodiols was synthesized and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. The reduction of a bicyclic α-methylene ketone, derived from natural (?)-limonene followed by epoxidation, gave the key epoxy alcohol intermediate. Ring opening of the oxirane ring with primary amines induced by lithium perchlorate afforded the required aminodiols. Substituent-dependent ring closure of the secondary aminodiols with formaldehyde resulted in both spirooxazolidines and a fused 1,3-oxazine. Cyclization reactions of the studied aminodiols, resulting in spirocyclic oxazolidines and an isomeric perhydro-1,3-oxazine-fused compound along with the possible iminium intermediates, were analyzed by a systematic series of comparative DFT models performed at the B3LYP/6-31+G(d,p) level of theory.
Hydrolysis of Phosphonothioates with a Binaphthyl Group: P-Stereogenic O-Binaphthyl Phosphonothioic Acids and Their Use as Optically Active Ligands and Chiral Discriminating Agents
Kuwabara, Kazuma,Maekawa, Yuuki,Minoura, Mao,Murai, Toshiaki
, p. 1375 - 1379 (2018)
The hydrolysis of phosphonothioates with a binaphthyl group afforded the first example of O-(2′-hydroxy)binaphthyl phosphonothioic acids in good to high yields and >95:5 diastereoselectivity. The reaction proceeds via an axis-to-center chirality-transfer reaction. The ability of these acids to act as chiral molecular auxiliaries was demonstrated by using them as optically active ligands for the asymmetric ethylation of benzaldehyde and as a chiral discriminating agent for chiral aliphatic amines.
Enantioselective alkylation of aldehydes with diethylzinc using a new catalyst system, ((R)-thiolan-2-yl)diphenylmethanol and metal alkoxides
Shiina, Isamu,Konishi, Katsuhiko,Kuramoto, Yu-suke
, p. 164 - 165 (2002)
Various optically active secondary alcohols are obtained by asymmetric alkylation of aldehydes with diethylzinc by way of a new catalyst system, ((R)-thiolan-2-yl)diphenylmethanol and several metal alkoxides. The transition states are also discussed in terms of experimental results and theoretical calculation.
