The protection of terminal ethynyl groups in Grignard syntheses

Zirconocene-Mediated, High-Yielding Macrocyclizations of Silyl-Terminated Diynes

“…Therefore, for preparation of the tetraphenylene diyne ( 4 ), the modified synthetic route given in Scheme was employed. Here, 4,4′‐diiodobiphenyl was coupled using a modified Stille protocol12 with 1‐(trimethylstannyl)‐4‐(trimethylsilylethynyl)benzene ( 5 )13 in dry DMF at 70 °C for 4 days to give the desired tetraphenylene diyne 4 . The crude material could be purified by recrystallization from hot toluene to give a white solid in 50 % yield.…”

“…Zirconocene dichloride (Strem), n ‐butyllithium solution (Aldrich), 4,4′‐dibromobiphenyl (Aldrich), 4,4′‐diiodobiphenyl (Aldrich), and trimethylsilylacetylene (GFS) were used as received. The compounds 1,4‐bis(trimethylsilylethynyl)benzene 1 ,10 4,4′‐bis(trimethylsilylethynyl)biphenyl 2 ,10 1‐bromo‐4‐(trimethylsilylethynyl)benzene,13 4,4″‐diiodoterphenyl,12 4‐(trimethylsilylethynyl)‐1‐(trimethylstannyl)benzene 5 ,13 and 3,3′‐dibromobiphenyl17 were prepared by literature procedures.…”

“…4,4′′′‐Bis(trimethylsilylethynyl)tetraphenyl (4) : In a Schlenk flask (100 mL) equipped with a stir bar, [Pd 2 (dba) 3 ] (0.340 g, 0.371 mmol) and AsPh 2 (0.454 g, 1.48 mmol) were loaded in the glove box. In a separate Schlenk flask (100 mL) Me 3 SnC 6 H 4 C≡CSiMe 3 5 13 (2.50 g, 7.42 mmol) and 4,4′‐diiodobiphenyl (1.00 g, 2.46 mmol) were loaded. This Schlenk flask was evacuated and backfilled before suspending the organics in dry DMF (30 mL).…”

4-[2-(Trimethylsilyl)ethynyl]benzoates: Synthesis and evaluation for mesomorphic properties of some novel calamitic molecules

“…Synthetic procedure for compound 2 [19] To a solution of 4-iodobenzoic acid (2.0 g, 1.0 mmol), copper (I) iodide (1.7 g, 1.13 mmol), palladium chloride (0.02 g, 0.15 mmol) and triphenylphosphine (2.1 g, 1.0 mmol) in triethylamine (7 ml), was added ethynyltrimethylsilane (1.2 g, 1.5 mmol) dropwise over 30 min. The resulting reaction mixture was then refluxed at 80 C for 24 h under an atmosphere of argon and monitored by TLC.…”

“…To our knowledge, 4-[2-(trimethylsilyl)ethynyl]benzoic acid 2 [19] has not been used for the preparation of mesogenic materials [20].…”