104013-23-2Relevant academic research and scientific papers
LipG9-mediated enzymatic kinetic resolution of racemates: Expanding the substrate-scope for a metagenomic lipase
Thomas, Juliana Christina,Alnoch, Robson Carlos,Costa, Allen Carolina dos Santos,Bandeira, Pamela Taisline,Burich, Martha Daniela,Campos, Suelem Kluconski,de Oliveira, Alfredo Ricardo Marques,de Souza, Emanuel Maltempi,Pedrosa, Fabio de Oliveira,Krieger, Nadia,Piovan, Leandro
, (2019)
Enzymes are the main biocatalysts of biological systems and nowadays they play an important role in asymmetric organic synthesis. Microorganisms are the main source for enzymes, however, just a very small portion of them are culturable at lab conditions and, as an alternative, metagenomics approaches allow new enzymes to be accessed from so-called “non-culturable” microorganisms. Several classes of metagenomic enzymes have been described in literature. Nevertheless, studies about their potential for asymmetric biotransformation are underexploited. Therefore, we present our recent efforts to establish the substrate-scope of LipG9, a metagenomic lipase, in enzymatic kinetic resolution (EKR) of chiral substances. LipG9 was previously isolated, immobilized and successfully applied in EKR of aliphatic alcohols. In this study, a series of resolvable chiral substances were assayed with LipG9, and secondary benzyl alcohols/esters were preferentially resolved in a much superior enantioselectivity (E > 200) than those described for aliphatic alcohols (E from 4 to 63). In an opposite way, Im-LipG9 did not present activity for tertiary alcohols, amines and lactones. When compared to commercial lipases, Im-LipG9 enantioselectivity was superior to Candida rugosa lipase and equivalent to Candida antarctica lipase B. Thus, the chemo and enantioselectivity of LipG9 in EKR reactions were identified and its potential for asymmetric synthetic approaches was demonstrated.
GENERAL BASE CATALYSIS OF THE ADDITION OF HYDROXYLIC REAGENTS TO UNSTABLE CARBOCATIONS AND ITS DISAPPEARANCE.
Richard,Jencks
, p. 1396 - 1401 (1984)
General base catalysis of the addition of ROH is significant for 1-phenylethyl carbocations of moderate stability and is most important for weakly basic alcohols. The Bronsted slope for catalysis of the addition of trifluoroethanol to the 1-(4-methoxyphenyl)ethyl carbocation is beta equals 0. 08. The development of positive charge on the attacking alcohol decreases with decreasing stability of the carbocation. It is concluded that the observed catalysis involves hydrogen bonding and represents the transition region between fully concerted, coupled general acid-base catalysis and specific acid catalysis with solvation of the proton in the transition state.
Combined lipase-catalyzed resolution/Mitsunobu esterification for the production of enantiomerically enriched arylalkyl carbinols
Bouzemi, Nassima,Aribi-Zouioueche, Louisa,Fiaud, Jean-Claude
, p. 797 - 800 (2006)
Several arylalkyl carbinols [1-indanol, 1-tetralol, 1-phenylethanol, 1-(1-naphthyl)ethanol, 1-(2-naphthyl)ethanol, 1-(4-methoxyphenyl)ethanol, 1-acenaphthenol] were deracemized through sequential combinations of lipase-catalyzed resolution and Mitsunobu inversion. The corresponding (R)-acetates were obtained in 72-83% yield and 89-99% ee.
Spatial effects of oxovanadium-immobilized mesoporous silica on racemization of alcohols and application in lipase-catalyzed dynamic kinetic resolution
Sugiyama, Koji,Oki, Yasuhiro,Kawanishi, Shinji,Kato, Katsuya,Ikawa, Takashi,Egi, Masahiro,Akai, Shuji
, p. 5023 - 5030 (2016)
We recently reported a new dynamic kinetic resolution (DKR) method based on the combination of lipase-catalyzed kinetic resolution of racemic alcohols and the V-MPS3-catalyzed in situ racemization of less reactive alcohol enantiomers. In V-MPS3, oxovanadium moieties were covalently bound to the inner surface of mesoporous silica (MPS) with a pore size of about 3 nm. The catalytic activity of V-MPS3 was much higher than that of related vanadium compounds; however, we could neither explain its unusually high activity nor confirm that the racemization predominantly occurred inside the V-MPS pores. Therefore, in this study, we prepared V-MPS2 and V-MPS4 from the corresponding MPS with pore diameters of approximately 2 nm and 4 nm, respectively and compared their racemization activities with that of V-MPS3 using some optically active alcohols with different molecular sizes and polarities. We discovered a positive correlation between the pore size of V-MPS and substrate racemization rate as well as the high polarity of the MPS pores. The results suggested that the racemization predominantly occurs in the pores of V-MPS and that a small pore size (2-4 nm) is essential to generate the polar environment of V-MPS, which probably accelerates the racemization by facilitating the C-O bond cleavage of the vanadate intermediates. Using V-MPS with a pore size suitable for each substrate, lipase/oxovanadium combo-catalyzed DKR could be applied to a wider range of alcohols including allyl alcohols, benzylic alcohols, and propargyl alcohols to give the corresponding esters in excellent isolated yields and enantioselectivities.
Enzymic Preparation of Enantiomerically Pure Secondary Alcohols. Ester Synthesis by Irreversible Acyl Transfer using a Highly Selective Ester Hydrolase from Pseudomonas sp.; an Attractive Alternative to Ester Hydrolysis
Laumen, Kurt,Breitgoff, Detlef,Schneider, Manfred P.
, p. 1459 - 1461 (1988)
A series of secondary alcohols (R)- and (S)-(1)-(3) and (5)-(9) of interest as attractive chiral auxiliaries were prepared in high chemical and optical yields via enzymic esterification under essentially anhydrous conditions by employing a highly selective ester hydrolase from Pseudomonas sp. and vinyl acetate as acyl donor.
Kinetic resolution strategies II: Enhanced enantiomeric excesses and yields for the faster reacting enantiomer in lipase mediated kinetic resolutions
Brown,Davies,De Sousa
, p. 813 - 822 (1993)
A strategy for the preparation of the faster reacting (R)-enantiomer of 1-(4-methoxyphenyl)ethanol with 95% ee in 37% overall yield via a double kinetic resolution strategy involving Pseudomonas fluorescens lipase mediated sequential acetylation and hydrolysis is described.
Practical P-chiral phosphane ligand for Rh-catalyzed asymmetric hydrogenation
Liu, Duan,Zhang, Xumu
, p. 646 - 649 (2005)
A highly electron-donating and conformationally rigid P-chiral bis(trialkylphospholane) ligand 2 (DuanPhos) has been prepared in both enantiomeric forms through a concise synthesis. Rh-2 complex has exhibited remarkably high enantio-selectivities (up to >99% ee) and reactivities (up to 10,000 TON) for the hydrogenation of a wide variety of functionalized prochiral alkenes (5 different types), which provides a very practical catalytic system for the preparation of various synthetically useful chiral compounds. Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005.
Construction of multiple, contiguous quaternary stereocenters in acyclic molecules by lithiation-borylation
Watson, Charlotte G.,Balanta, Angelica,Elford, Tim G.,Essafi, Stphanie,Harvey, Jeremy N.,Aggarwal, Varinder K.
, p. 17370 - 17373 (2014)
Lithiation of carbamates followed by borylation provides a powerful method for the homologation of boron reagents. However, when applied to hindered systems (secondary carbamates with tBu-boronic esters) for the construction of two quaternary centers, thi
Green methodology for enzymatic hydrolysis of acetates in non-aqueous media via carbonate salts
Merabet-Khelassi, Mounia,Houiene, Zahia,Aribi-Zouioueche, Louisa,Riant, Olivier
, p. 828 - 833 (2012)
Herein we report a new approach to enantiomerically enriched acetates using a lipase-catalyzed hydrolysis in non-aqueous media by alkaline carbonate salts. The use of sodium carbonate in the enzymatic hydrolysis with Candida antarctica lipase B (CAL-B) of racemic acetates shows a large enhancement of the reactivity and selectivity of this lipase. The role of the carbonate salts, the amount and the nature of the alkaline earth metal on the efficiency of this new pathway are investigated. The enzymatic kinetic resolution of acetates 1a-9a, by enzymatic-carbonate hydrolysis under mild conditions is described. In all cases, the resulting alcohols and remaining acetates were obtained in high ee values (up to >99%) while the selectivities reached E >500.
On the use of succinic anhydride as acylating agent for practical resolution of aryl-alkyl alcohols through lipase-catalyzed acylation
Bouzemi, Nassima,Debbeche, Hanane,Aribi-Zouioueche, Louisa,Fiaud, Jean-Claude
, p. 627 - 630 (2004)
A comparison is carried out of the E-values recorded in the lipase-catalyzed resolution of a series of secondary aryl-alkyl alcohols with enol esters versus succinic anhydride. Whereas all the substrates could be resolved by a proper choice of the lipase/enol ester couple with moderate (E=50) to good (E>100) enantioselectivities, only some of them showed satisfactory enantioselectivity (E>50) with the use of succinic acid as acylating agent. Notably, indanol and 1-quinolin-3-yl-ethanol were resolved in a practical way, with E>100 and E>80, respectively.
