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Modular Syntheses of Star‐Shaped Pyridine, Bipyridine, and Terpyridine Derivatives by Employing Sonogashira Reactions
Author(s) -
Trawny Daniel,
Kunz Valentin,
Reissig HansUlrich
Publication year - 2014
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201402778
Subject(s) - terpyridine , sonogashira coupling , chemistry , pyridine , combinatorial chemistry , bipyridine , organic chemistry , crystal structure , catalysis , palladium , metal
A simple and flexible synthesis for a series of star‐shaped pyridine, bipyridine, and terpyridine derivatives is reported by using a modular approach that combines the use of a ligand, spacer, and core unit. A fairly efficient method to prepare 4′‐nonafloxy‐functionalized terpyridine derivatives is described. The building blocks that contain the functionalized pyridine, bipyridine, or terpyridine derivatives were linked to different C 3 ‐symmetrical core units. In most cases, Sonogashira reactions were employed in the crucial final steps of the synthesis. A star‐shaped dodecafluorinated compound was also prepared in a straightforward fashion. A simple procedure for the preparation of partially silylated 1,3,5‐triethynylbenzene derivatives is presented, which provides an approach to C 2 ‐symmetrical star‐shaped compounds that have only one terpyridine and two terphenyl units as “dummy” ligands. The absorption and emission spectra of the fully conjugated C 3 ‐symmetrical pyridine derivatives were systematically investigated, and fairly large Stokes shifts were observed.