Neue chirale Triazoliumsalze in der Carben-katalysierten intramolekularen gekreuzten Benzoin-Reaktion

In nature many metal free catalytic reactions are accomplished in enzymes. The broad facilities of organocatalysis as a selective and environment-friendly synthetic method has only been recognized recently by chemists. This thesis deals with the synthesis of novel chiral polycylic triazolim salts as pre-catalysts for N-heterocyclic carbenes. Their application was shown in the first asymmetric intramolecular aldehyde-ketone benzoin reaction. Different alpha-hydroxy-tetralone, - indanone- and -chromanone-derivatives could be obtained with generation of a quaternary stereogenic center with high enantioselectivities. This alpha-hydroxy-ketones are structural motifs of many bioactive natural products. Thus, synthetic concepts for the synthesis of (S)-eucomol and (S)-lacinilen C methylether have been followed. Furthermore, an efficient proline-catalyzed asymmetric intramolecular 5-enolexo aldol reaction for the cis-selective synthesis of 3-hydroxy-2,3-dihydrobenzofuranes has been developed. After a simple 1,2-addition the corresponding tertiary alcohols can be obtained which are structural motifs in many bioactive natural products such as the coumarins smyrindiol and vaginidiol.

Grantor dc:publisher

Mainz

Year dc:date

2007

Author dc:creator

• Niemeier, Oliver

Contributors dc:contributor

• Enders, Dieter

• info:eu-repo/classification/ddc/540
• Katalyse
• Organische Chemie
• Naturstoff
• Wirkstoff
• Stereoselektive Synthese
• Organische Synthese
• Asymmetrische Synthese
• Chemie
• Organokatalyse
• Carben
• Benzoin-Reaktion
• intramolekular
• asymmetrisch
• organocatalysis
• carbene
• natural product
• benzoin reaction
• intramolecular

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-123257%22

OAI identifier oai:identifier

oai:publications.rwth-aachen.de:61613