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Showing 1 to 11 of 11 for “"SAMP/RAMP-Hydrazone"”.
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Asymmetric synthesis of lignans and of α-heteroaryl)alkylamines employing the SAMP-/RAMP-hydrazone method
… 1,2-addition of heteroarenyllithium species to SAMP-/RAMP-hydrazones, has been developed. Moreover the novel methodology was successfully applied to the synthesis of biologically interesting compounds such as a-aminoacids and b-aminosulfones.
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Asymmetrische Synthese neuer planar- und zentral-chiraler Ferrocenylliganden
… ferrocenyl diketones via our SAMP/RAMP-hydrazone method. Keystep is the stepwise diastereoselective ortho-metalation of 1,1'-bisbenzoylferrocene-bis-SAMP-hydrazone followed by trapping of various types of electrophiles. Within our studies we demonstrate the broad applicability …
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Untersuchungen zur diastereo- und enantioselektiven Synthese von Matsuon und asymmetrische Synthese von anti-1,2-Sulfanylaminen
… the desired natural product described using the SAMP- /RAMP-hydrazone method. Several chiral building blocks were synthesized in high diastereomeric and enantiomeric excesses but the title compound could not be obtained. In the second part of the thesis a flexible diastereo- and enantioselective …
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Zur asymmetrischen Synthese von C-Azanucleosiden und 2-Amino-1,3-diolen
… The different approaches envisaged, using the SAMP- /RAMP-Hydrazone methodology to synthesese the desired compound are herein described. Several chiral building blocks were synthesized in high diastereomeric and enantiomeric excess however the titled compound could not be obtained. In the …
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Zur asymmetrischen Synthese von Beta-Thio-Alpha-Aminosäuren
… amino acids described using chiral Amines or the SAMP-/RAMP-hydrazone methodology. Nearly all retrosynthetic approaches are starting with Bromacetaldehyde-Diethylacetale, which is nucleophil substituted with thiolates. After acidic hydrolyses of the acetals the correspending sulphur-substituted …
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Asymmetrische Pinakolkupplungen
… both strategies were investigated. Using the SAMP / RAMP hydrazone method several a-chiral aldehydes and ketones were obtained in a four step procedure in moderate to excellent enantiomeric excesses (ee = 56 - ³98%). The reductive coupling of these a-chiral carbonyl compounds succeeded with …
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Asymmetrische Synthese von 2-Methyl-substituierten 1,3-Diolen
… with (S)-1-amino-2-methoxymethylpyrrolidine (SAMP) to the respective SAMP-hydrazone proved to be an excellent platform for general asymmetric synthesis. Consequently in 1989 we published a stereoselective a-alkylation of the respective SAMP-hydrazone followed by oxidative auxiliary cleavage to …
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Versuche zur ersten Totalsynthese des Aglycons der Cripowelline A und B und erste asymmetrische Synthese von Tropional
… of both enantiomers of Tropional based on the SAMP/RAMP-hydrazone method developed by Enders et al. Starting from the enantiomerically pure propanale hydrazones the desired alpha-alkylated hydrazones could be obtained in yields greater than 70% by deprotonation with LDA at -100øC. Subsequent …
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Asymmetrische Synthese von Sordidin, 7-epi-Sordidin und von Polyoeinheiten mit quartären Stereozentren
… has been achieved. Starting from dioxanone RAMP-hydrazone the desired C-7 epimers were prepared in 39% overall yield as a 1.5: 1 diastereomeric mixture over 14 steps. The epimers could be separated by preparative GC and thus, each of them could be obtained in high diastereomeric and …