Development of Viable Synthetic Approaches to Highly Functionalized Small Ring Systems - Synthesis of Novel Cyclopropylacrylates as Monomers for Low-Shrinkage Polymer-Composites

Development of Viable Synthetic Approaches to Highly Functionalized Small Ring Systems - Synthesis of Novel Cyclopropylacrylates as Monomers for Low-Shrinkage Polymer-Composites

by Viktar Bahutski
Doctoral thesis
Date of Examination:2004-01-21
Date of issue:2005-07-13
Advisor:Prof. Dr. Armin de Meijere
Referee:Prof. Dr. Hartmut Laatsch
Persistent Address: http://dx.doi.org/10.53846/goediss-2185

 

 

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Abstract

English

Twenty-eight new alkyl 2-cyclopropylacrylates with various substitution patterns were synthesized from readily available precursors applying appropriately modified variants of standard transformations or newly developed synthetic protocols. Towards the synthesis of target cyclopropyl acrylates a preparative-scale procedur vapor-phas yrolysis o bicyclopropylidene to methylenespiropentane to provide pure methylenespiropentane on a 17.4 g scale, a large-scal reparative protocol fo 2-methylenecyclopropanecarboxaldehyde, two highly efficien for hydrolysis of alkyl acrylates and partia ers, and new esterification protocol for acylation o sterically congested alcohols were developed. Subsequent cyanohydrin formation from an aldehyde, alcoholysis of a cyanohydrin to an a-hydroxycarboxylic acid ester, Simmons-Smith cyclopropanations of cycloalken-1-yl hydroxyacetates, oxidatio ig methylenation of an a-ketocarboxylic acid ester afforded target cyclopropylacrylates on overall yields ranged from 33 to 54% 0]alken-(n+3)-yl)pyruvates were prepared by dirhodiu tetraacetate-catalyzed cyclopropanation of the corresponding alkenes wit methy 32 58 opropanations of EWG-substituted a-cyclopenteylacetic esters or their isomeric precursors with SHI carbenoid (CF3COOZnCH2I) were investigated. Thus, a protocol fo one-pot cyclopropanation-methylenation of (cyclo)alkylidenemalonates and their analogues, readily accessible by the KNOEVENAGEL reaction, has been developed.The behavior of the synthesized cyclopropylacrylates unde merization condition been investigate (IVOCLAR Vivadent) t demonstrate for alkyl acrylates bearing in a-position 2- o mprove ty in comparison to DECVCP. It was concluded that suc could b bstitut mmerciall lable dilutents i dental composites. Thus le protoco as developed which allow one to obtain methyl 2-(bicyclo[3.1.0]hex-1-yl)acrylate (130) in three steps from hydroxyacetate 81 on a 50 scal in 75 overall yield tive protocol fo 5-exo-trig/3-exo-trig cascade cyclization of various 1,6-enyne been developed which involved a new catalyti haracterized by the lowest loading volume among the published ones. By this approach, the bicyclic 2-cyclopropylacrylate 130 as well as its structural analogues 207-209, which are promising new low-shrinkage monomers an are inaccessibl by other synthetic routes, can be synthesized in high yield.Twenty-eight new alkyl 2-cyclopropylacrylates with variou ns wer
Keywords: hydrolysis; oxidations; cycloadditions; cyclopropanation; Wittig reaction; enyne cyclisomerization; palladium; catalysis; ring-opening polymerization; vinylcyclopropanes
Schlagwörter: hydrolyse; oxidation; cycloaddition; cyclopropanierung; Wittig reaktion; enin cycloisomerisierung; palladium; katalyse; ring-öffnung polymerisation; vinylcyclopropane
 
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