3-Bromothiophene

clear colourless to slightly yellow liquid. It is not soluble in water, but can dissolve in common organic solvents such as chloroform, benzene, ether, and tetrahydrofuran.

3-Bromothiophene can be used as a reactant to synthesize:
3,3-Bithiophene via borylation followed by Suzuki coupling.
3-Alkylthiophenes by NiDPPP++ catalyzed cross-coupling with Grignard reagents.
3-Lithiothiophene by treating with n-butyllithium in hexane.
Derivatives of thienylenic α, ωdiformylαoligothiophenes.
N-(2-(3-bromothiophen-2-yl)phenyl)methanesulfonamides by coupling at the 2-position with N-arylmethanesulfonamides, mediated by iodobenzene diacetate (178721).

3-Bromothiophene is used in the preparation of derivatives such as thienylenic alpha, μ-diformyl-alpha-oligothiophenes and 3-lithiothiophene. It is also used in the synthesis of 3-lithiothiophene by reacting with n-butyllithium.

Preparation of 3-bromothiophene using 2,5-dibromothiophene
2,5-Dibromothiophene (121g, 0.5 moles), tris (3,6-dioxaheptyl) amine (1.0g, 0.003 mole), thiophene (500 cm3) and sodium amide (58.5g, 1.5 mole) were successively charged to a flask which had previously been purged with nitrogen. The reaction mixture was stirred and heated under nitrogen at 50-60°C for 6 hours. The product, after work up as described in Example 3, was found to contain 138.5g 3-bromothiophene and 2.6g 2-bromothiophene. The yield of 3-bromothiophene was 85% and the monobromothiophenes were in the ratio of 2 parts 2-bromothiophene to 98 parts 3-bromothiophene.

3-Bromothiophene is an electron-rich aromatic hydrocarbon bromide. The bromine atom in it has good electrophilicity. It can perform a Suzuki coupling reaction under the catalysis of metal palladium, and react with different aryl or alkenyl borates. The corresponding substitution products are generated. This reaction is one of the very important methods in organic synthesis, which can build C-C bonds and form complex organic molecular structures.

Journal of the American Chemical Society, 74, p. 2965, 1952 DOI: 10.1021/ja01132a004
Synthetic Communications, 11, p. 25, 1981 DOI: 10.1080/00397918108064278