51. |
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52. |
- Högberg, Hans-Erik
(författare)
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Exploiting enantioselectivity of hydrolases in organic solvents
- 2008
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Ingår i: Organic Synthesis with Enzymes in Non-Aqueous Media. - Weinheim : Wiley-VCH Verlagsgesellschaft. - 9783527318469 - 9783527318469 ; , s. 73-112
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In modern organic chemistry the synthesis of chiral enantiopure compounds is an extremely important objective. To achieve this, biocatalysts have emerged as key tools. The broad reactivity of hydrolytic enzymes combined with their ability to discriminate between enantiomers make them ideal catalysts for resolving racemic organic compounds to provide enantiomerically enriched products. This chapter gives an overview of how the enantioselectivity of hydrolases can be exploited to furnish virtually enantiopure compounds via kinetic resolution of racemic compounds and desymmetrisation of symmetric compounds. Enantioselectivity and E-values are discussed. Reversibility of hydrolase-catalysed reactions and how it can be avoided by using various irreversible acyl donors as well as the determination and optimization of enantioselectivity are briefly discussed. The bulk of the chapter consists of selected examples of hydrolase catalysed reactions of some important classes of compounds. Thus the usefulness of hydrolase-catalyzed reactions is demonstrated by several examples of reactions in organic solvents of primary, secondary, tertiary alcohols, various amines, and acid derivatives.
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53. |
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54. |
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55. |
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56. |
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57. |
- Högberg, Hans-Erik, et al.
(författare)
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Synthesis of Some Bicyclophanes.
- 1982
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Ingår i: Acta Chemica Scandinavica, B-Organic chemistry and biochemistry. - 0302-4369. ; 36:10, s. 661-667
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Tidskriftsartikel (refereegranskat)
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58. |
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59. |
- Isaksson, Dan, et al.
(författare)
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Enantiomerically enriched cryptone by lipase catalysed kinetic resolution
- 2006
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Ingår i: Tetrahedron. - : Elsevier BV. - 0957-4166 .- 1362-511X. ; 17:2, s. 275-280
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Tidskriftsartikel (refereegranskat)abstract
- Thiophenol was added to racemic cryptone (4-isopropyl-2-cyclohexene-1-one) and the resulting 1,4-addition products, cis- and trans-4-isopropyl-3-(phenylsulfanyl)cyclohexanone) were separated and the latter reduced to rac-1,3-cis-1,4-trans-4-isopropyl-3-(phenylsulfanyl)cyclo¬he¬xanol which was subjected to lipase catalysed resolution by acylation catalysed by CAL-B (Candida antarctica lipase B). The remaining alcohol was separated from the produced acetate, which was hydrolysed to the alcohol. The enantiomeric alcohols so obtained were oxidised. The initial products, probably sulfoxidoketones spontaneously decomposed to furnish enantiomerically enriched (R)- and (S)-cryptone with up to 76% and 98% ee, respectively.
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60. |
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