2-Bromothiophene → 2-(Trimethylsilylethynyl)thiophene

Participants

Reaction Steps

Under a nitrogen atmosphere a solution of 12.0 grams (0.074 mole) of 2-bromothiophene, 9.0 grams (0.092 mole) of trimethylsilylacetylene, and 120 ml of triethylamine was stirred, and 0.52 gram (catalyst) of bis(triphenylphosphine)palladium(II) chloride and 0.28 gram (catalyst) of copper(I) iodide were added. Upon completion of addition, the reaction mixture was stirred at ambient temperature during an 18 hour period. After this time the reaction mixture was concentrated under reduced pressure to a residue. The residue was dissolved in diethyl ether, and the solution was washed with two portions of an aqueous 10% ammonium chloride solution, one portion of water, and one portion of an aqueous solution saturated with sodium chloride. The organic layer was dried with sodium sulfate and filtered. The filtrate was concentrated under reduced pressure to a residue. The residue was subjected to column chromatography on silica gel. Elution was accomplished using 10% methylene chloride in hexane. The appropriate fractions were combined and concentrated under reduced pressure yielding 11.0 grams of 2-trimethylsilylethynylthiophene. The nmr spectrum was consistent with the proposed structure.

Provenance & Evidence