Protophane und Polyaromaten, XXVIII. Wahlweise α‐ und γ‐Lithiierung des 2‐(2‐Thienyl)pyridins und analoger Heterodiaromaten durch Wechsel des Lösungsmittels

Abstract

2-(2-Thienyl)pyridin (1) wird durch n-Butyllithium oder Lithium-diisopropylamid in Tetrahydrofuran praktisch ausschliefllich in der a-Stellung der Thienylgruppe lithiiert. Bei Anwendung von n-oder tert-Butyllithium in Ether erfolgt die Lithiierung dagegen weitgehend bzw. ausschlieRlich in der y-Stellung dieser Gruppe. Ahnliche Verhaltnisse wurden bei der Lithiierung von 2-Chlor-6-(2-thienyl)pyridin (6) und 2-(2-Thienyl)chinolin (9) beobachtet. -Die Synthese von 1 wurde verbessert; 6 wurde erstmals synthetisiert. Durch Umsetzung der Lithiierungsprodukte von 1, 6 und 9 rnit Trimethylsilylchlorid wurden sechs silylierte Heterodiaromaten erhalten. Protophanes and Polyaromatics, XXVIII Lithiation of 2-(2-Thienyl)pyridine and Analogous Heterodiaromatics Alternatively in a-or y-Position by Changing the Solvent2-(2-Thienyl)pyridine (1) is lithiated in tetrahydrofuran by n-butyllithium or lithium diisopropylamide nearly exclusively in the a-position of the thienyl group. In contrast, application of n-or tert-butyllithium in ether effects lithiation mainly or wholly in the y-position of this group. Lithiation of 2-chloro-6-(2-thienyl)pyridine (6) and 2-(2-thienyl)quinoline (9) occurs analogously. -For 1 an improved synthesis is described, whereas 6 was synthesized for the first time. By the reaction of the lithiation products of 1, 6, and 9 with trimethylsilyl chloride six silylated heterodiaromatics were obtained.

Square Planar (SP-4) and Octahedral (OC-6) Complexes of Platinum(II) and -(IV) with Predetermined Chirality at the Metal Center

“…A systematic study by Kauffmann showed that, in the case of thienylpyridine, it is possible to make a selective lithiation on the thiophene ring at position 3‘, being the correct position for a cyclometalation to occur . This reaction was successfully performed with ligands 2 and 4 .…”

Synthesis and characterization of novel substituted pyrrole, thiophene and furans

“…Over the last few years, the application of such polymers to flexible, light and small electronic and optical devices have been actively carried out. [13][14][15] Despite a large number of studies, [19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] which comprise polymeric heterocyclic systems such as imidazolyl-, thiazolyl-, or quinolylpyrroles, thiophenes or furans, there is no work about the synthesis and properties of these simple linked two ring systems in the literature. Several methods are available for the synthesis of two ring systems, which contain the pyrrole, thiophene or furan ring linked to an imidazole, thiazole, or quinoline ring.…”

Chiral Cyclometalated Platinum(II) and Palladium(II) Complexes with Derivatives of Thienylpyridine as Ligands: Helical Distortion of the Square Planar (SP-4) Geometry

“…Scheme features the pathway followed for the synthesis of complexes 7 , 8 , and 10 . Two steps can be distinguished: lithiation of the ligand on carbon C3‘ of the thiophene ring and metal exchange with M(SEt 2 ) 2 Cl 2 , where M is either palladium or platinum. This method has already been applied in many cases reported in the literature.…”