J. Sauer, D. Heldmann
Apr 23, 1998
Citations
0
Influential Citations
22
Citations
Journal
Tetrahedron Letters
Abstract
Ethynyltributyltin 2 cycloadds to 5-phenyl-1,2,4-triazine-3-carboxyclic acid methyl ester 1 to furnish mainly 4-tributylstannyl-6-phenyl-pyridine-2-carboxyclic acid methyl ester 3a besides a small amount of the 3-tributylstannyl isomer 3b. The tributyltin substituent of pyridine 3a can be replaced by Pd-catalyzed acylation and arylation, by halogenation and protonation to yield functionalized pyridines 4 – 7, which are not available by direct cycloaddition of the corresponding alkynes.