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Development and Application ofEnzymatic Asymmetric Synthesis ofFunctionalized Alcohols
Stockholm University, Faculty of Science, Department of Organic Chemistry. (Jan-Erling Bäckvall)
2015 (English)Licentiate thesis, comprehensive summary (Other academic)
Abstract [en]

The main focus of this thesis lies on enzymatic asymmetric organic reactions. In the first part ofthis work, we looked into the lipase-catalyzed transesterification and hydrolysis at the molecularlevel. It was shown that the low enantioselectivity of CALB-catalyzed transesterification of a δ-functionalized alkan-2-ol to its acetate does not correlate at all with the high enantioselectivity ofthe CALB-catalyzed hydrolysis of the corresponding acetate in water. This lack of correlation isunusual and for unfunctionalized alkan-2-ol derivatives there is a very good correlation betweenthe enantioselectivity of transesterification of the alcohol and hydrolysis of the correspondingacetate with a high enantioseletivity in both cases. The results confirm previous predictions frommolecular modeling. The water effect was mimicked by CALB variant Ala281Ser, whichshowed an enhanced enantioselectivity in transesterification of δ-functionalized alkan-2-olscompared to wild type CALB.

In the second part of the thesis, enzymatic kinetic resolution to resolve 1-substituted buta-2,3-dien-1-ol was studied. The initial goal was to use Shvo catalyst as racemization catalyst for anenvisioned dynamic kinetic resolution of this substrate. To our surprise, 2,3-dihydrofurans wasformed when α-allenic alcohols was treated with Shvo catalyst and the chiral center that endedup in the product was unchanged. Based on the KR and cycloisomerization, we furthermoredeveloped a one-pot procedure combining kinetic resolution and cyclization to optically pureoxygen-containing heterocycles. The mechanism of the Ru-catalyzed cycloisomerization wasstudied and a Ru-carbenoid was suggested as a crucial intermediate for forming the 2,3-dihydrofurans.

Place, publisher, year, edition, pages
Stockholm: Stockholms universitets förlag, 2015. , 36 p.
National Category
Natural Sciences Chemical Sciences
Identifiers
URN: urn:nbn:se:su:diva-124400OAI: oai:DiVA.org:su-124400DiVA: diva2:885832
Presentation
2016-01-11, 12:21
Supervisors
Available from: 2015-12-21 Created: 2015-12-21 Last updated: 2015-12-21Bibliographically approved

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Yang, Bin
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