Regioselective functionalization of trisubstituted pyridines using a bromine-magnesium exchange.
A tosyloxy substituent in position 2 allows a highly regioselective Br/Mg exchange reaction on 3,5-dibromopyridine derivatives using iso-PrMgCl.LiCl. The resulting functionalized pyridylmagnesium reagents react with various electrophiles in position 3. Acylated pyridines of this type can be readily converted into pyrazolo [3,4-b] pyridines.
Ren
Hongjun
H
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377, München, Germany.
Knochel
Paul
P