53152-69-5Relevant academic research and scientific papers
Towards a General Understanding of Carbonyl-Stabilised Ammonium Ylide-Mediated Epoxidation Reactions
Novacek, Johanna,Roiser, Lukas,Zielke, Katharina,Robiette, Rapha?l,Waser, Mario
supporting information, p. 11422 - 11428 (2016/08/03)
The key factors for carbonyl-stabilised ammonium ylide-mediated epoxidation reactions were systematically investigated by experimental and computational means and the hereby obtained energy profiles provide explanations for the observed experimental results. In addition, we were able to identify the first tertiary amine-based chiral auxiliary that allows for high enantioselectivities and high yields for such epoxidation reactions.
The search for an easily-prepared sparteine surrogate
Foley, Vera M.,Cano, Rafael,McGlacken, Gerard P.
, p. 1160 - 1167 (2016/11/04)
(?)-Sparteine has proven itself to be a highly efficient and versatile ligand. However, in recent years it has become difficult to source. In addition the (+)-enantiomer is also not readily available. Here we report a suite of chiral diamines as potential sparteine surrogates. Chiral trans-1,2-diaminocyclohexane is commercially available in both enantiomeric forms and the parent structure can be easily modified. New (and known) chiral diamines have been tested in the asymmetric silylation of N-Boc pyrrolidine, N-Boc piperidine, the α-alkylation of dimethylhydrazones and in the rearrangement of meso-epoxides. While none match the selectivity of the highly evolved natural product, there is certainly potential for this class of diamine ligands to perform in a diverse set of asymmetric transformations.
Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
supporting information, p. 17662 - 17668 (2015/02/02)
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
Enantioselective addition of methyllithium to aromatic imines catalyzed by C2 symmetric tertiary diamines
Kizirian, Jean-Claude,Cabello, Noemi,Pinchard, Laurent,Caille, Jean-Claude,Alexakis, Alexandre
, p. 8939 - 8946 (2007/10/03)
Enantioselective addition of methyllithium to aromatic imines catalyzed by C2 symmetric tertiary diamines is described. Eleven diamines have been tested, for which dramatic effect of the nitrogen substitution has been observed. Diamines bearing hindered group close to the nitrogen led to racemic product while homologous hindered diamines led to the best results. Enantiomeric excess up to 74% could be achieved. An explanation of the absolute configuration of the product obtained is given considering the mechanism of the reaction.
Simple 1,2-diamine ligands for asymmetric addition of aryllithium reagents to imines
Cabello, Noemi,Kizirian, Jean-Claude,Gille, Segolene,Alexakis, Alexandre,Bernardinelli, Gerald,Pinchard, Laurent,Caille, Jean-Claude
, p. 4835 - 4842 (2007/10/03)
Enantioselective addition of various aryllithium reagents to aromatic imines was catalyzed (20 mol-%) by readily accessible 1,2-diamines to afford a wide range of protected diarylmethylamines in up to 94 % enantiomeric excess. Furthermore, the absolute configuration of these arylation products was determined by using X-ray crystallography. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.
Facile cleavage of Si-C bonds during the sol-gel hydrolysis of aminomethyltrialkoxysilanes - A new method for the methylation of primary amines
Adima, Augustin,Bied, Catherine,Moreau, Joel J. E.,Man, Michel Wong Chi
, p. 2582 - 2588 (2007/10/03)
The reaction of chloromethyltriethoxysilane with (1R,2R)-bis(methylamino) cyclohexane (1) afforded the corresponding bis-silylated compound 2. The sol-gel hydrolysis of 2 did not give the expected bridged silsesquioxane owing to quantitative Si-C-bond cleavage. Instead, silica and (1R,2R)-bis(dimethylamino) cyclohexane (3) were obtained. This reaction was exploited to propose a new route for the methylation of amines. Such methylation reaction of amines could be extended to other amines and provides a new method for the selective monomethylation of primary amines. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004.
Conceptually new chiral tertiary C2 symmetric diamines in asymmetric synthesis
Kizirian, Jean-Claude,Caille, Jean-Claude,Alexakis, Alexandre
, p. 8893 - 8895 (2007/10/03)
New chiral diamines were prepared, based on the cyclohexane diamine core. The two different substituents on each nitrogen allow this heteroatom to become a stereogenic center upon chelation with a metal, such as lithium. The enantioselective addition of MeLi to imines, with ee's up to 68%, illustrates the validity of this concept.
Lithium diisopropylamide solvated by monodentate and bidentate ligands: Solution structures and ligand binding constants
Remenar, Julius F.,Lucht, Brett L.,Collum, David B.
, p. 5567 - 5572 (2007/10/03)
6Li and 15N NMR spectroscopic studies of lithium diisopropylamide ([6Li]LDA and [6Li,15N]LDA) in toluene/pentane solutions containing a variety of mono- and polydentate ligands are reported. LDA forms exclusively dimers in the presence of n-BuOMe, Et2O, t-BuOMe, THF, 2- methyltetrahydrofuran, 2,2-dimethyltetrahydrofuran, tetrahydropyran, dimethoxyethane, N,N,N',N'-tetramethylethylenediamine, and MeOCH2CH2NR2 (NR2 = NMe2, NEt2, pyrrolidino). Addition of 1,2-dipyrrolidinoethane and (2-pyrrolidinoethyl)dimethylamine provides monomer-dimer mixtures. Treatment of LDA with trans-N,N,N',N'-tetramethylcyclohexanediamine (TMCDA) or trans- 1-(dimethyl-amino)-2-isopropoxycyclohexane in hydrocarbons afford exclusively monomers. Sparteine binds only reluctantly, giving a mixture of unsolvated oligomers and monomer. Competitions of the ethereal ligands vs TMCDA afford binding constants and associated free energies for dimer solvation which are correlated with those obtained previously for lithium hexamethyldisilazide.
THE REACTIONS OF N,N-DIMETHYLPHOSPHORAMIDIC DIFLUORIDE WITH TRANS-2-SUBSTITUTED CYCLOALKANOLS
Fokin, E. A.,Sadovnikov, S. V.,Sosnov, A. V.
, p. 57 - 64 (2007/10/02)
An interaction between N,N-dimethylphosphoramidic difluoride and cyclic alcohols containing hydroxyl, alkylamine and methylthiol groups in the trans-β-position was performed. Trans-1-ethylcyclopentane-1,2-diol and trans-2-(N-alkylamino)cyclopentanols react with N,N-dimethylphosphoramidic difluoride to yield 1-ethyl-6-oxabicyclo(3.1.0)hexane and 6-alkyl-6-azabicyclo(3.1.0)hexane, respectively. In the case of trans-2-(N,N-dialkylamino)cyclopentanols and cyclohexanols, such reaction gives a salt of phosphorodifluoridic acid and the corresponding cyclic N,N,N',N'-tetraalkyl-1,2-diamine whereas trans-2-methylthiocyclopentanol is converted to a salt of phosphorodifluoridic acid and N,N-dimethyl-N-(2-methylthiocyclopentyl)amine. Some of described reactions appear to be applicable for the synthesis of various organic compounds, e.g. phosphorylated 2-N,N-dialkylaminocyclopentanethiols. Key words: N,N-dimethylphosphoramidic difluoride, N,N-dimethylphosphoramidothioic difluoride, phosphorodifluoridic acid, phosphorylated dialkylaminocyclopentanethiol, N,N-dialkylaminocycloalkanol, N,N,N',N'-tetraalkyl-1,2-diamine.
