A New Bromination Method for Phenols and Anisoles:  NBS/HBF₄·Et₂O in CH₃CN

Aluminium Powder‐Catalyzed Regio‐ and Stereoselective Aminobromination of α,β‐Unsaturated Carbonyl Compounds and Simple Olefins with the p‐Toluenesulfonamide/ N‐Bromosuccinimide (TsNH2‐NBS) System

“…Sb (antimony), Pb (lead), and Mg (magnesium) also afforded the aminobrominated products in moderate to good yields (50-67%, entry 12,16,17). Ge (germanium) was less effective (19%, entry 14).…”

“…[12] Furthermore, the electrophilic aromatic substitution reaction on the benzene ring took place when 3,5-dimethoxychalcone was used as substrate in our reaction. This observation is clear evidence that a positive bromine …”

Regioselective Monobromination of Free and Protected Phenols

“…We chose these two highly polar solvents as it is known that polar solvents drive the bromination reaction through the stabilization of bromocyclohexadienone-type intermediates. [17] DMF [18] as well as MeCN [15] have been described previously as good solvents for nuclear bromination reactions of aromatic systems with NBS. However, the bromination of a polyphenol with NBS in THF has only been reported once, [19] and has only rarely been used for the bromination of monosubstituted methoxy-or benzyloxyanilines.…”

“…[14] Aromatic electrophilic substitution of activated systems with NBS is generally favored in polar solvents such as DMF and CH 3 CN. [15] Ionic liquids [16] such as 1-butyl-3-methylimidazolium hexafluorophosphate have recently been reported as the solvents of choice for these kinds of substrates. We report herein a new and mild procedure for the regioselective monobromination of benzenetriol, its methyl and isopropyl ethers, and its tertbutyl carbonate.…”

A Novel Synthesis of Bromobenzenes Using Molecular Bromine

“…The manufacture of a wide range of bulk and fine chemicals, including flame retardants, disinfectants and antibacterial and antiviral drugs, involves bromination reactions [1]. Aryl bromides are often used in the syntheses of aryl esters, aryl olefins and other useful classes of compounds, consequently, numerous methods for the bromination of aromatics have been reported in the literature [2][3][4][5][6][7][8][9][10][11][12][13][14]. Some of the drawbacks of classical direct bromination of aromatic systems using elemental bromine as the reagent are the waste of bromine and the difficulties in selectively achieving monobromination (especially in the case of electron-rich compounds).…”