Transition-metal-free BF₃-mediated oxidative and non-oxidative cross-coupling of pyridines.
We report a BF3-mediated direct alkynylation of pyridines at C(2) by using a variety of alkynyllithium reagents (oxidative cross-coupling). Moreover, we have developed a novel transition-metal-free cross-coupling method between alkylmagnesium reagents and 4-substituted pyridines, such as isonicotinonitrile and 4-chloropyridine, by employing BF3⋅OEt2 as a promoter. The combination of these methods enabled us to efficiently prepare a range of di-, tri-, and tetrasubstituted pyridines.
Department of Chemistry, Ludwig-Maximilians-Universität München, Butenandtstrasse 5-13, Haus F, 81377 München (Germany).
Quan
Q
Chen
Thierry
T
León
Paul
P
Knochel
D000480:Alkynes / Q000737:chemistry; D001880:Boranes / Q000737:chemistry*; D002384:Catalysis; D010084:Oxidation-Reduction; D011725:Pyridines / Q000737:chemistry*; D028561:Transition Elements / Q000737:chemistry
D000480:Alkynes; D001880:Boranes; D011725:Pyridines; D028561:Transition Elements; C021274:boron trifluoride
BF3; alkynyllithium compounds; chloranil; cross-coupling; nitrogen heterocycles