61925-50-6Relevant academic research and scientific papers
Convergent Catalytic Asymmetric Synthesis of Esters of Chiral Dialkyl Carbinols
Fu, Gregory C.,Yang, Ze-Peng
supporting information, (2020/03/30)
Because chiral dialkyl carbinols, as well as their derived esters, are significant as intermediates and end points in fields such as organic, pharmaceutical, and biological chemistry, the development of efficient approaches to their asymmetric synthesis is an important endeavor. In this report, we describe a method for the direct catalytic enantioselective synthesis of such esters, beginning with an alkyl halide (derived from an aldehyde and an acyl bromide), an olefin, and a hydrosilane, catalyzed by nickel, an earth-abundant metal. The method is versatile, tolerating substituents that vary in size and that bear a range of functional groups. We further describe a four-component variant of this process, wherein the alkyl halide is generated in situ, thus obviating the need to isolate either an alkyl electrophile or an alkylmetal, while still effecting an alkyl-alkyl coupling. Finally, we apply our convergent method to the efficient catalytic enantioselective synthesis of three esters that are bioactive themselves or that have been utilized in the synthesis of bioactive compounds.
Chiral 2-(2-hydroxyaryl)alcohols (HAROLs) with a 1,4-diol scaffold as a new family of ligands and organocatalysts
Dilek, ?mer,Tezeren, Mustafa A.,Tilki, Tahir,Ertürk, Erkan
supporting information, p. 268 - 286 (2017/12/06)
Efficient and modular syntheses of chiral 2-(2-hydroxyaryl)alcohols (HAROLs), novel 1,4-diols carrying one phenolic and one alcohol hydroxyl group, have been developed which led to generation of a small library of structurally diverse HAROLs in enantiomerically pure form. Of the different HAROLs examined, a HAROL based on the indan backbone exhibited the highest activity and enantioselectivity in the 1,2-addition of certain organometallic compounds to aldehydes in the presence of Ti(OiPr)4 (up to 97% y, 88% ee) and performed as a hydrogen-bond donor organocatalyst in the Morita-Baylis-Hillman reaction, promoted by trialkylphosphines.
Mechanistic implications of the enantioselective addition of alkylzinc reagents to aldehydes catalyzed by nickel complexes with α-amino amide ligands
Escorihuela, Jorge,Burguete, M. Isabel,Ujaque, Gregori,Lledós, Agustí,Luis, Santiago V.
, p. 11125 - 11136 (2016/12/07)
The enantioselective alkylation of aldehydes catalysed by nickel(ii)-complexes derived from α-amino amides was studied by means of density functional theory (DFT) and ONIOM (B3LYP:UFF) calculations. A mechanism was proposed in order to investigate the origin of enantioselectivity. The chirality-determining step for the alkylation was the formation of the intermediate complexes with the involvement of a 5/4/4-fused tricyclic transition state. The predominant products predicted theoretically were of (S)-configuration, in good agreement with experimental observations. The scope of the reaction was examined and high yields and enantioselectivities were observed for the enantioselective addition of Et2Zn and Me2Zn to aromatic and aliphatic aldehydes.
Novel C2-symmetric chiral O,N,N,O-tetradentate 2,2-bipyridyldiolpropane ligands: Synthesis and application in asymmetric diethylzinc addition to aldehydes
Shih, Yi-Shan,Boobalan, Ramalingam,Chen, Chinpiao,Lee, Gene-Hsian
, p. 327 - 333 (2014/04/03)
First synthesis of C2-symmetric chiral O,N,N,O-tetradentate 2,2-bipyridyldiolpropane ligands is described. The Mukaiyama-Michael reaction was applied as an important reaction for the synthesis of 2,2-bipyridylpropane 9. Among the ligands synthesized, ligand 11 exhibits excellent chiral induction (up to 97% ee) in diethylzinc addition to various aldehydes. The use of additional Lewis acid such as Ti(OiPr)4 in diethylzinc addition reaction is not required for the present catalytic system.
The synthesis of chiral amino diol tridentate ligands and their enantioselective induction during the addition of diethylzinc to aldehydes
Zhang, An-Lin,Yang, Li-Wen,Yang, Nian-Fa,Liu, Yan-Ling
, p. 289 - 297 (2014/04/03)
A series of C2-symmetric chiral amino diol tridentate ligands 3a-g were prepared from achiral bulky organolithiums, achiral bulky primary amines, and optically active epichlorohydrin (ECH). The prepared C 2-symmetric chiral amino diol tridentate ligands were capable of inducing enantioselectivity in the model reaction of aromatic and aliphatic aldehydes with diethylzinc with an ee of up to 96%. The enantioselectivity can be modulated by adjusting the steric hindrance of the achiral reagents employed in the synthesis of the chiral ligand. The configuration of the addition product depended on the configuration of the amino diol ligands, which can be simply controlled as desired by using the ECH with the desired configuration during the preparation of the ligand.
C2 symmetrical nickel complexes derived from α-amino amides as efficient catalysts for the enantioselective addition of dialkylzinc reagents to aldehydes
Escorihuela, Jorge,Altava, Belen,Burguete, M. Isabel,Luis, Santiago V.
, p. 551 - 558 (2013/07/27)
A series of C2 symmetrical 1:2 Ni:L complexes derived from α-amino amides were studied for the enantioselective addition of dialkylzinc reagents to aldehydes. Different structural elements on the ligands seem to play an important role in determining the observed enantioselectivity. Through optimization of structure and reaction conditions, the best ligand provided secondary alcohols in excellent yields (up to 98%) and enantioselectivity of up to 99% ee for (R)-enantiomer. A transition state model has been proposed to explain the observed enantioselectivities based on computational calculations at the DFT level. Very interestingly, calculations suggest a coordination model of the aldehyde to the metal complex through association of a lone pair of the carbonyl oxygen to the hydrogen atom of an amino group.
Synthesis of chiral pyridylphenols for the enantioselective addition of diethylzinc to aldehydes
Wu, Pei-Shan,Chen, Chinpiao
experimental part, p. 768 - 781 (2012/08/27)
Chiral 8-substituted 2-(8,10,10-trimethyl-6-aza-tricyclo[7.1.1.0 2,7]undeca-2(7),3,5-trien-5-yl)-phenols were prepared from a high enantiopurity (>97% ee) of (1R)-(+)-α-pinene, and assessed in the enantioselective addition of diethylzinc to substituted benzaldehydes, giving the (S)-alcohols with enantiomeric excess ranging from 33% to 89%. Interestingly, in all cases, except for those of ortho-chlorobenzaldehyde, ortho- and para-methoxybenzaldehydes, the ee was >71%. The plot of the Hammett substitution constants vs. enantiomeric excess of the diethylzinc addition to either the ortho- or para-substituted benzaldehydes shows a linear correlation.
The synthesis of new oxazoline-containing bifunctional catalysts and their application in the addition of diethylzinc to aldehydes
Coeffard, Vincent,Mueller-Bunz, Helge,Guiry, Patrick J.
experimental part, p. 1723 - 1734 (2009/06/27)
The straightforward preparation of new modular oxazoline-containing bifunctional catalysts is reported employing a microwave-assisted Buchwald-Hartwig aryl amination as the key step. Covalent attachment of 2-(o-aminophenyl)oxazolines and pyridine derivati
One-way biohydrogen transfer for oxidation of sec-alcohols
Lavandera, Ivan,Kern, Alexander,Resch, Verena,Ferreira-Silva, Bianca,Glieder, Anton,Fabian, Walter M. F.,De Wildeman, Stefaan,Kroutil, Wolfgang
supporting information; experimental part, p. 2155 - 2158 (2009/05/27)
(Chemical Equation Presented) Quasi-irreversible oxidation of sec-alcohols was achieved via biocatalytic hydrogen transfer reactions using alcohol dehydrogenases employing selected ketones as hydrogen acceptors, which can only be reduced but not oxidized. Thus, only 1 equiv of oxidant was required instead of a large excess. For the oxidation of both isomers of methylcarbinols a single nonstereoselective short-chain dehydrogenase/reductase from Sphingobium yanoikuyae was identified and overexpressed in E. coli.
Asymmetric anti-Prelog reduction of ketones catalysed by Paracoccus pantotrophus and Comamonas sp. cells via hydrogen transfer
Lavandera, Ivan,Hoeller, Brigitte,Kern, Alexander,Ellmer, Ursula,Glieder, Anton,de Wildeman, Stefaan,Kroutil, Wolfgang
, p. 1954 - 1958 (2008/12/22)
A broad range of ketones including methyl-aryl-, methyl-alkyl-, cyclic and sterically hindered ketones were reduced to the corresponding anti-Prelog alcohols with moderate to excellent stereoselectivities by employing lyophilised cells of Paracoccus pantotrophus DSM 11072 and Comamonas sp. DSM 15091 via hydrogen transfer. The reduction equivalents were provided using 2-propanol as a hydride donor. For instance, acetophenone was reduced to the corresponding (R)-enantiomer with >99% ee.
