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28th August 2013 @ 13:49
This post is compatible for submission to ChemSpider Reactions. See [blog=44639]ChemSpider Reactions template - help and further information[/blog] for help when using it. Reaction information *#Reaction file [data]38478[/data] *Reaction file type CDX *Procedure A 250 mL Schlenk flask containing 4-bromothioanisole (2.031 g, 10.00 mmol), PdCl2 (89 mg, 0.50 mmol, 5 mol%), PPh3 (262 mg, 1.00 mmol, 10 mol%) and CuI (190 mg, 1.00 mmol, 10 mol%) was evacuated and refilled with argon before adding distilled MeCN (100 mL). Distilled iPr2NH (4.22 mL, 3.036 g, 30.00 mmol, 3.00 eq.) was then added, followed by trimethylsilylacetylene, TMSA (1.70 mL, 1.179 g, 12.00 mmol, 1.20 eq.) dropwise. The reaction mixture was heated to 70 °C and stirred for 25 h; the conversion was estimated to be almost quantitative by GC (SD_FASTD, product RT 5.2 minutes). The solvent was evaporated, the residue was dissolved in DCM (250 mL), washed with water and brine, dried over anhydrous MgSO4. Evaporation of the solvent afforded the crude product (2.616 g); this was adsorbed on a small amount of silica gel and column chromatographed using (20/1) hexane/DCM as eluent, followed by (3/1) hexane/DCM. A fraction of title compound containing starting material (higher Rf) was columned again using hexane as eluent, and then changing to (5/1) hexane/DCM gradually. The pure product (orange oil, Rf 0.14 in (20/1) hexane/DCM; 1.689 g, 7.66 mmol, yield 77 %) was found to be unstable on silica when exposed to light (2D TLC) *Yield (%) 77 % *Type of Yield Isolated pure product Reference(s) [data]38366[/data][data]38480[/data] Further information Compound 21: trimethyl(2-(4-(methylthio)phenyl)ethynyl)silane For multistep reactions (or their steps): Overall reaction? False For overall reaction - links to child reaction steps   For step in multistep reaction - link to previous reaction step   For step in multistep reaction - link to following reaction step Reaction 22: Sonogashira Coupling: 2-(4-(2-(4-bromophenyl)ethynyl)phenyl)methylthioether
Attached Files
reactionscheme_21.cdx
PhD Thesis - 16Sep2010_final p116-117.pdf