Print version Print setup

Stille coupling of thiophene to 1,2,4,5-tetrabromo-3,6-bis(dodecyloxy)benzene; 2,2',2'',2'''-(3,6-bis(dodecyloxy)benzene-1,2,4,5-tetrayl)tetrathiophene

SyntheticPage 952
Submitted Jul 20, 2021, published Aug 03, 2021
Kathryn Allen (kathryn.allen@millersville.edu), Landon Kurtz (lmkurtz@millersville.edu)
A contribution from Allen Group @ MU of PA


			Reaction Scheme: Stille coupling of thiophene to 1,2,4,5-tetrabromo-3,6-bis(dodecyloxy)benzene

Chemicals Used

1,2,4,5-tetrabromo-3,6-bis(dodecyloxy)benzene 

Toluene, anhydrous, 99.8% Aldrich

2-(tributylstannyl)thiophene, 97% Aldrich

tetrakis(triphenylphosphine)Palladium(0), 99% Strem Chemicals Inc.

Procedure

A dry three-necked round-bottom flask equipped with a condenser, three septa, and a stir bar was purged with nitrogen gas for twenty minutes, after which anhydrous toluene (4 mL), 1,2,4,5-tetrabromo-3,6-bis(dodecyloxy)benzene (0.250 g, 0.328 mmol, 1 eq) and 2-(tributylstannyl)thiophene (0.612 g, 1.64 mmol, 5 eq) were added. A catalytic amount of tetrakis(triphenylphosphine)palladium(0) was added and the flask was set to reflux at 120° Celsius for 72 hours. The product was verified by thin layer chromatography (2% ethyl acetate in hexanes, Rf =0.73). The solution was then cooled to room temperature and toluene was removed in vacuo. The residue was dissolved in chloroform and washed with a sodium hydroxide solution (10%, 200mL, 3x) for the removal of tin. After drying the organic layer over magnesium sulfate, filtering, and concentrating in vacuo, the crude material was recrystallized from methanol to give the product as a fluffy white solid (0.230 g, 0.297 mmol, 91% yield).

Author's Comments

The Stille is exceptionally robust to moisture and air. However, the flask and condenser were attached to a Schlenk line and purged with nitrogen for 20 minutes by blowing nitrogen through the top of the condenser and out an outlet in the side of the flask prior to starting the reaction. Dry solvent was used. 
All glassware was treated in a base bath after the Stille reaction and the Stille waste was segregated in its own waste container to remove tin by-products. Organotin reagents are toxic and should be handled with correct PPE under the supervision of an experienced chemist.
The peak, on the 13C NMR, at 29.649 ppm did not show due to resolution issues, but should be noted it is present.

Data

1H NMR (400 MHz, CDCl3): δ 7.274 (m, 4H), 6.904 (m, 8H), 3.189 (t, 4H, J = 6.6 Hz), 1.27 (m, 20H), 1.14 (m, 12H),  0.940 (m, 14H).

13C NMR (400 MHz, CDCl3): δ 152.276, 136.816, 130.433, 129.075, 126.305, 126.062, 73.300, 31.915, 29.767, 29.649, 29.631, 29.524, 29.441, 29.342, 29.130, 25.517, 22.679, 14.110.

ESI positive mode on AXION 2 Time of Flight Mass Spectrometer
Calculated [M+H]: 775.3705
Found [M+H]: 775.3717

Supplementary Information

Carbon NMR (LMK15Carbon.pdf)
Proton NMR_2 (LMK15Proton.pdf)

This page has been viewed approximately 243 times since records began.

Get structure file (.cdx, .sk2, .mol)

Keywords: alkyl/alkenyl/aryl halides, heterocyclic compounds, transition metal catalysed

Post new comment
Loading ...