C-H, N-H coupling of azole and thiophene derivatives takes place in the presence of a catalytic amount of Cu(OAc) 2 and an additive. The reaction of azoles smoothly occurs with several amines and amides catalyzed by 20 mol% of Cu(OAc) 2-2PPh 3 and 4 equiv. of NaOAc under O 2 or in the presence of Ag 2 CO 3 under N 2. The coupling reaction leads to a facile synthesis of a Nsubstituted analogue of 2,5-diarylthiazole, which shows photoluminescent properties with extended -conjugation. Spectroscopic characteristics of the obtained thiazole derivatives are discussed by measurements of UV-vis absorption and photoluminescent spectra. Under the reaction conditions using Ag 2 CO 3 as an additive and Cu(OAc) 2-2PPh 3 as a catalyst, thiophene derivatives also react with 2-pyrrolidone to undergo C-H, N-H amidation.

Preparation of 2,2¤-bithiophene derivatives bearing ω-alkenyl groups at the 3,3¤-positions and ring-closing metathesis reactions of the obtained compound were performed. The reaction of bithiophene bearing 3-butenyl substituents 1 with 5 mol % Grubbs 1st generation catalyst underwent ring-closing metathesis (RCM) to afford the cyclized product 7 showing winding vine-shaped molecular asymmetry in up to 88% yield. Enantioselective RCM was also achieved by the use of chiral Schrock Hoveyda molybdenum-alkylidene catalyst in up to 87% ee.

Dehydrobrominative polycondensation of 2-bromo-3-hexylthiophene proceeded with TMPMgBr•LiBr and (TMP) 2 Mg•2LiBr, formed by LiTMP and MgBr 2 , which was found to serve as a surrogate of the Knochel−Hauser base TMPMgCl•LiCl, and head-to-tail-type regioregular poly(3-hexylthiophene) was obtained with high efficiency. The regioregular poly(3-hexylthiophene) was also found to be obtained by one-shot addition of 2-bromo-3-hexylthiophene as a monomer, magnesium amide, and a nickel catalyst, suggesting that complete formation of metalated thiophene species is not an essential requisite for the successful polymerization with a nickel catalyst. This method was employed for the preparation of tolylterminated polythiophene by an aryl group with narrow molecular weight distribution using (o-tolyl)NiCldppp as a catalyst.

MITSUDA, S.; FUJIWARA, T.; KIMIGAFUKURO, K.; MONGUCHI, D.; MORI*, A.; Tetrahedron 68 (2012) 18, 3585-3590, http://dx.