83867-96-3Relevant articles and documents
Identification of an Esterase Isolated Using Metagenomic Technology which Displays an Unusual Substrate Scope and its Characterisation as an Enantioselective Biocatalyst
Gavin, Declan P.,Murphy, Edel J.,Foley, Aoife M.,Castilla, Ignacio Abreu,Reen, F. Jerry,Woods, David F.,Collins, Stuart G.,O'Gara, Fergal,Maguire, Anita R.
supporting information, p. 2466 - 2474 (2019/03/11)
Evaluation of an esterase annotated as 26D isolated from a marine metagenomic library is described. Esterase 26D was found to have a unique substrate scope, including synthetic transformations which could not be readily effected in a synthetically useful manner using commercially available enzymes. Esterase 26D was more selective towards substrates which had larger, more sterically demanding substituents (i. e. iso-propyl or tert-butyl groups) on the β-carbon, which is in contrast to previously tested commercially available enzymes which displayed a preference for substrates with sterically less demanding substituents (e.g. methyl group) at the β-carbon. (Figure presented.).
Lipase catalysed kinetic resolutions of 3-aryl alkanoic acids
Deasy, Rebecca E.,Brossat, Maude,Moody, Thomas S.,Maguire, Anita R.
experimental part, p. 47 - 61 (2011/04/18)
Hydrolase catalysed kinetic resolutions leading to a series of 3-aryl alkanoic acids (≥94% ee) are described. Hydrolysis of the ethyl esters with a series of hydrolases was undertaken to identify biocatalysts that yield the corresponding acids with excellent enantiopurity in each case. Steric and electronic effects on the efficiency and enantioselectivity of the biocatalytic transformation were also explored.
Lipase catalyzed acylation of primary alcohols with remotely located stereogenic centres: the resolution of (±)-4,4-dimethyl-3-phenyl-1-pentanol
Sabbani, Sunil,Hedenstroem, Erik,Andersson, Jimmy
, p. 1712 - 1720 (2008/02/11)
Enantioselective acylation of some (±)-3-alkyl-3-phenyl-1-propanols was performed with enzymes as catalysts. Moderate enantiomeric ratios (E), ranging up to E = 11.6, were obtained. In the resolution, some of the lipases selectively acylated the (+)-enant
On the mechanism of the addition of organolithium reagents to cinnamic acids
Aurell, María José,Ba?uls, María José,Mestres, Ramon,Mu?oz, Elena
, p. 1067 - 1074 (2007/10/03)
The regioselectivity of the addition of tert-butyllithium to cinnamic acid is subject to reaction conditions and to substituent electronic effects. Significant effects are observed in the presence of several additives including a radical trap such as α-methylstyrene. Competition experiments by addition of the organolithium reagent to mixtures of substituted cinnamic acids show that the relative rates of both conversion of the starting acids and formation of the 1,3-adducts are subject to electronic effects, whereas rates for 1,4-addition are independent of the substituents. These features are in agreement with a polar addition mechanism, but a fast SET equilibrium followed by slow radical combination would be possible as well.
Addition of organolithium reagents to cinnamic acids
Aurell, Maria Jose,Banuls, Maria Jose,Mestres, Ramon,Munoz, Elena
, p. 831 - 846 (2007/10/03)
Reaction of tert-butyllithium with p- and m-substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
Stereocontrol in the intramolecular Buchner reaction of diazoketones
Maguire, Anita R.,Buckley, N. Rachael,O'Leary, Patrick,Ferguson, George
, p. 4077 - 4091 (2007/10/03)
Rhodium(II) acetate catalysed intramolecular Buchner cyclisation of a series of diazoketones 1 proceeds with excellent diastereoselectivity to produce the trans substituted azulenones 2, which exist as a rapidly equilibrating cycloheptatriene-norcaradiene system, from which the norcaradiene tautomers can be efficiently trapped as PTAD cycloadducts 4. The cyclisation-cycloaddition sequence can be conducted in either a stepwise or a tandem process, leading to the pentacyclic systems 4 as a single diastereomer in each case. In the reaction of diazoketone If intramolecular cyclopropanation competes with cyclisation to the aromatic ring.
Contrasting behaviour of (E)-3-(trimethylsilyl)- and (E)-3-phenylpropenoic acids towards n-butyl- and tert-butyllithium
Kruithof, K. J. H.,Mateboer, A.,Schakel, M.,Klumpp, G. W.
, p. 62 - 65 (2007/10/02)
The title compounds 2 and 9 react with tert-buthyllithium to give considerable amounts of 'anti-Michael' adducts 3 and 10, respectively, in which the tert-butyl group is bonded to C-2.A single-electron-transfer (SET) mechanism is proposed for these reacti
