ISSN:
1434-193X
Keywords:
Cycloadditions
;
Cross-coupling
;
Halogens
;
Nitrogen heterocycles
;
Tin
;
Chemistry
;
General Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
-Recently, we reported on cycloadditions between electron-deficient heterodienes and tributyl(ethynyl)tin, which provide a new pathway to stannylated pyridazines and, in one special case, pyridines. In order to broaden the synthetic scope of these reactions, we have developed hetero [4+2] cycloaddition reactions between a number of tailor-made 1,2,4-triazines 5-9 (acting as heterodienes), and tributyl(ethynyl)tin (acting as dienophile). The desired 1,2,4-triazines are readily available, in moderate to very good yields, by the condensation reactions of appropiate carbamidrazones and glyoxals. These cycloadditions open up a novel route to regiospecifically stannylated 2,2′-bi- and 2,2′,6′,2′′-terpyridines 1-4, 11 in good yields. The stannanes 1-4, 11 are versatile synthetic intermediates, and with this strategy various substituents can be incorporated directly by substitution of the stannyl group, as was shown for halogens and carbon electrophiles under Stille conditions.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
