RSS-Feed abonnieren
DOI: 10.1055/s-2002-33331
Microwave-Assisted Enantioselective
Heck Reactions: Expediting High
Reaction Speed and Preparative
Convenience
Publikationsverlauf
Received
14 June 2002
Publikationsdatum:
23. August 2002 (online)


Abstract
Palladium-catalyzed asymmetric Heck reactions have been performed using high temperature conditions with the aid of controlled microwave dielectric heating. Significant enantioselectivities of up to 92% ee were obtained under non-inert conditions utilizing the previously reported thermostable palladium-phosphineoxazoline catalytic system. With microwave irradiation, reaction times of hours instead of days were obtained. Enantiomeric purities and conversions were found to be strongly dependent on both the choice of the aryl triflate, the reaction temperature, the solvent and the base. Examples of asymmetric arylations of electron-rich as well as neutral cyclic alkenes are presented.
Key words
asymmetric catalysis - Heck reaction - arylations - regioselectivity - palladium