Chiral enol acetates derived from prochiral oxabicyclic ketones using enzymes

Carnell, Andrew J.; Swain, Simon A.; Bickley, Jamie F.

doi:10.1016/s0040-4039(99)01809-2

Cited by 12 publications

(10 citation statements)

References 11 publications

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“…The improved performance of PREP in the present instance is in agreement with earlier observations that such lipase preparations show greater enantioselectivity (as compared to the lyophilized powder) in dry hexane [ 16 ] and ionic liquids [ 4 ].…”

Section: Resultssupporting

confidence: 92%

Enantioselective transacetylation of (R,S)-β-citronellol by propanol rinsed immobilized Rhizomucor miehei lipase

Majumder

Shah

Gupta

2007

Chemistry Central Journal

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Background: Use of enzymes in low water media is now widely used for synthesis and kinetic resolution of organic compounds. The frequently used enzyme form is the freeze-dried powders. It has been shown earlier that removal of water molecules from enzyme by rinsing with n-propanol gives preparation (PREP) which show higher activity in low water media. The present work evaluates PREP of the lipase (from Rhizomucor miehei) for kinetic resolution of (R,S)-β-citronellol. The acylating agent was vinyl acetate and the reaction was carried out in solvent free media.

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Section: Resultssupporting

confidence: 92%

Enantioselective transacetylation of (R,S)-β-citronellol by propanol rinsed immobilized Rhizomucor miehei lipase

Majumder

Shah

Gupta

2007

Chemistry Central Journal

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“…This disadvantage is overcome if one enantiomer of the starting racemic mixture is converted into a meso ‐configured product, thus allowing further resolution cycles upon reconversion into the racemic mixture. Carnell et al applied this “ meso trick” concept for the two‐step desymmetrization of oxabicyclic ketones (Scheme ) 48. The presence of bridgehead substituents and the olefinic bridge have been crucial for the success of the enzymatic resolution employing a lipase from Humicola sp.…”

Section: Desymmetrization Of Meso‐configured 8‐oxabicyclo[321]ocmentioning

confidence: 99%

8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐ones: Application to the Asymmetric Synthesis of Polyoxygenated Building Blocks

2004

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The development and design of reliable and efficient methods for the construction of chiral building blocks are crucial in modern natural product synthesis. 8-Oxabicyclo[3.2.1]oct-6-en-3-ones are readily accessible scaffolds with defined stereochemical features which have been exploited for non-aldol approaches to the preparation of chiral building blocks. Strategies for their enantioselective synthesis, including asymmetric cycloaddition methods, desymmetrization protocols, and "racemic switch operations", are presented and evaluated.

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“…1 The shallow active site allows proteases to accept sterically hindered substrates 2,3 and also polar substrates, since one substituent remains in water. 5,6 For example, subtilisins and chymotrypsin favour ester and amides of phenylalanine. 5,6 For example, subtilisins and chymotrypsin favour ester and amides of phenylalanine.…”

Section: Analyticsmentioning

confidence: 99%

“…1,2 Enolate equivalents, such as silyl enol ethers and enol esters, can be made using chiral lithium amide bases at low temperature, although poor selectivity can be a problem, particularly with nonconformationally locked ketones. 5 Similarly, enol esters derived from 4,4-disubstituted cyclohexanones can be resolved using Pseudomonas fluorescens lipase (PFL) in tetrahydrofuran (THF). 4 Enol esters derived from 8-oxabicyclic ketones can be resolved in excellent selectivity (E ¼ 45-48) using silica-absorbed butanol-rinsed enzyme preparation (BREP) Humicola sp.…”

Section: Desymmetrization Of Prochiral Ketones Using Enzymesmentioning

confidence: 99%

Kinetic Resolutions Using Biotransformations

Gadler

Faber

Savile

et al. 2009

Practical Methods for Biocatalysis and Biotransformations

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Sulfatases are a heterogenic group of hydrolytic enzymes which catalyse the cleavage of the sulfate ester bond yielding the corresponding alcohol and hydrogen sulfate. In contrast to the more commonly employed hydrolytic enzymes, such as proteases, esterases and lipases, they show not only enantioselectivity -by preference of a given substrate enantiomer over its mirror-image counterpart -but also stereoselectivity with respect to the stereochemical course of their action. Depending on the enzyme, sulfate ester hydrolysis may proceed either through retention or inversion of configuration at the chiral carbon centre (Scheme 3.1). Whereas breakage of the SÀO bond leads to retention, CÀO bond cleavage results in inversion of configuration (Scheme 3.1). 1 The rare feature of double selectivities makes them top candidates for the deracemization 6 of sec-alcohols via enantio-convergent hydrolysis of their corresponding sulfate esters. 2 Overall, retaining sec-alkylsulfatase activity has been detected in Planctomycetes spp. (such as Rhodopirellula baltica DSM 10527; 3 complementary inverting sulfatase activity was found in Actinomycetes (e.g. Rhodococcus ruber DSM 44541 2,4 ), Archaea (e.g. Sulfolobus spp. 5 ) and pseudomonads. 7 Among the latter group, Pseudomonas sp. DSM 6611 was identified as top candidate by displaying excellent stereo-and enantio-selectivities for a range of sec-alkyl sulfate esters by transforming the (R)-enantiomer of the rac-sulfate ester into the corresponding (S)-alcohol (Scheme 3.2). 7 Practical Methods for Biocatalysis and BiotransformationsEdited

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Chiral enol acetates derived from prochiral oxabicyclic ketones using enzymes

Cited by 12 publications

References 11 publications

Enantioselective transacetylation of (R,S)-β-citronellol by propanol rinsed immobilized Rhizomucor miehei lipase

Enantioselective transacetylation of (R,S)-β-citronellol by propanol rinsed immobilized Rhizomucor miehei lipase

8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐ones: Application to the Asymmetric Synthesis of Polyoxygenated Building Blocks

Kinetic Resolutions Using Biotransformations

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