1. Magnesium turnings (1.61g, 0.066gatoms) in dry THF (100mL) under nitrogen was treated with a little of 2-bromothiophene (10.0g, 0.06mol) in THF (50mL). Warming initiated the reaction and the remainder added over 45 in. After 3.5h and a further 15 min. reflux, the cooled solution (0-5 C) was transferred dropwise by canula to a mixture of 2,6-dibromopyridine 13.08g, 0.055mol), PdCl2.dppe (0.5g) and dry THF (50mL) under nitrogen at -5 C. After 10h at 30 C ether was added (100mL), the solution washed with 4M HCl solution (sat., 150mL), then water. The dried and evaporated solution yielded an oil which was distilled (b.p. 150 C/0.1mm) to give 2-bromo-6-(2-thienyl)pyridine as a colourless liquid(8.5g, 59%).
  2. Thiophene (20.0g, 0.24mol) in dry THF (150mL) at -40 C under nitrogen was treated with n-butyllithium (0.24mol), stirred for 30 min. and then at -10 C for 30 min. This solution was cooled to -50 C and trimethyl borate 88g, 0.85mol) added over 1h. After a further 30 min. at -50 C the solution was warmed to ambient, neutralised with 2M HCl ether extracted, and the ether layer extracted 3 times with 3M NaOH. The aqueous layer was acidfied at 0-10 C and then extracted with ether (3x) and evaporated to give waxy white solid (37.4g, 79%) used without further purification.
  3. A mixture of 2,6-dibromopyridine (1.00g, 4.22 mmol), tetrakis-(triphenyl- phosphine)palladium[0] (0.175g), toluene (30mL), water 30mL), KF (1.0g) and thiophenboronic acid (2.5g) were refluxed under nitrogen for 4h. The toluene layer was washed with water, dried, evaporated and flash chromatographed (SiO2, PE/EtOAc 7:3) to give ,6-bis-(2-thienyl)pyridine (TPT for short) (0.91g, 90%), m.p. 78.5-9.5 C.
  4. To Mg (0.30g, 0.012gatoms)in dry THF (20mL) under nitrogen was added dropwise 1,2-dibromoethane (1.85g, 9.85mmol) in THF (30mL) and the solution refluxed for 50 min. In a separate flask, n-butyllithium (9.02mmol) was added to TPT (1.00g., 4.0mmol) in dry THF (20mL) at -40 C under nitrogen and after a further 30 min. at -40 C warmed to 0 C for 30 min., cooled to -60 C and the above MgBr2 solution added. After 30 min. at -60 C the solution was warmed to ambient to give the bis-Grignard reagent used directly as below.
  5. To the above solution was added a solution of 2-bromo-6-(2-thienyl)pyridine (2.41g, 0.01mol) and PdCl2.dppb) in dry THF 20mL) and the mixture refluxed for 4h. Removal of the THF and addition of CHCl3 gave a solution that was washed with sat. NH4Cl then water, dried and evaporated to give a yellow solid that was flash chromatographed (SiO2, PE/CH2Cl2 6:4) to give TPTPTPT (1.24g, 57%) as yellow crystals from ethyl acetate, m.p.117.5-8.5 C.

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