Vanadium-katalysierte, asymmetrische Epoxidierung von Allylalkoholen

A protocol for the vanadium-catalysed asymmetric epoxidation of allylic alcohols using enantiopure hydroxamic acids as ligands is described. The newly synthesised hydroxamic acids were derived from bicyclo[2.2.1]heptanes containing chiral centres, as well as from planar chiral [2.2]paracyclophanes and ferrocenes. Best results involving enantioselectivity of the epoxide formation were achieved using ligands with the [2.2]paracyclophane framework. Further studies towards the optimisation of the epoxidation method were carried out, and bulky aliphatic substituents at the nitrogen of the hydroxamic acids were shown to led to an increase in the enantiomeric excess of the products obtained. The readily available tert-butyl hydroperoxide was found to be the oxidant of choice. Environmentally friendly and halide free toluene was used as the solvent. Applying the optimised reaction conditions to the epoxidation of various allylic alcohols containing two or three substituents furnished the corresponding epoxides in good to excellent yields and with an enantiomeric excess of up to 71%.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2001

Author dc:creator

• Kühn, Toralf

Contributors dc:contributor

• Bolm, Carsten

• info:eu-repo/classification/ddc/540
• Chemie
• Allylalkohol
• Epoxidation
• Asymmetrische Reaktion
• Vanadiumkomplexe
• Imine
• Katalysator
• Hydroxamsäurederivate
• Palladiumkomplexe
• Phosphine

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

ger

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-118736%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A56648