A three-component synthesis of beta-alkoxy-beta-keto-enamides--flexible precursors for 4-hydroxypyridine derivatives and their palladium-catalysed reactions.
The flexible three-component reaction of lithiated alkoxyallenes with nitriles and carboxylic acids provided a series of highly functionalised beta-alkoxy-beta-ketoenamide derivatives. Upon base induced cyclisation and conversion to 4-pyridyl nonaflates various palladium-catalysed coupling reactions could be employed. The efficacy of this approach to functionalised pyridine derivatives was demonstrated by a fairly short route to a key intermediate suitable for a Glenvastatin synthesis. After Sonogashira couplings of alkynes with 4-pyridyl nonaflates subsequent cyclisations led to highly fluorescent [2,3c]furopyridine derivatives, whereas Suzuki reactions afforded 4-pyridyl stilbenes and by photocyclisation a highly substituted benzoisoquinoline derivative.
Lechel
Tilman
T
Institut für Chemie und Biochemie, Freie Universität Berlin, Takustr. 3, 14195, Berlin, Germany.
Dash
Jyotirmayee
J
Eidamshaus
Christian
C
Brüdgam
Irene
I
Lentz
Dieter
D
Reissig
Hans-Ulrich
HU