Regioselective bromination of organic substrates by LDH-CO32−–Br− promoted by V2O5–H2O2

A Green Protocol for the Bromination and Iodination of the Aromatic Compounds using H5IO6/NaBr and H5IO6/NaI in the Water

“…Recently, the oxidative halogenation of organic compounds by halides have emerged as an important alternative for the synthesis of such haloderivatives. [19][20][21][22][23][24][25][26][27][28][29][30] Despite the broad choice of options, however, many bromination and iodination methodologies are cumbersome, costly and harsh or involve the use of toxic heavy metals, volatile organic solvents, or elemental halogenes which are highly corrosive, toxic or self-sublimating. In addition, there are some environmental hazards with respect to handling them.…”

Steric Hindrance Effect Leading to Regioselective Bromination of Phenols with HBr

“…62～63 ℃ (lit. [15] 63～65 ℃); 1 H NMR (600 MHz, CDCl 3 ) δ: 7.23 (d,J＝1.8 Hz,1H),7.16 (dd,J＝8.4,2.4 Hz, 1H), 6.64 (d,J＝8.4 Hz,1H) 01,133.61,129.82,126.32,116.60,112.61,15.75;MS (EI) m/z: 188,186,168,141,117,107,89,77,63. 4-Bromo-2-methoxyphenol (3c): [16] Colorless oil. 1 H NMR (600 MHz, CDCl 3 ) δ: 7.05～6.88 (m, 2H), 6.79 (d,J＝8.4 Hz,1H), 5.54 (br s, 1H), 3.87 (s, 3H); 13 C NMR (150 MHz, CDCl 3 ) δ: 147.32,144.91,124.23,115.87,114.24,111.68,56.23;MS (EI) m/z: 204,202,189,187,161,159,145,143,133,131,117,108,94,79,63. 4-Bromo-2-fluorophenol (3d): [17] Colorless oil.…”

Regioselective Electrophilic Aromatic Bromination: Theoretical Analysis and Experimental Verification

“…Moreover, aryl bromides have been used as classical precursors to organolithium and Grignard reagents as well as in benzyne generation and nucleophilic aromatic substitution [10,11]. The most common synthetic method for preparing aryl bromides is electrophilic aromatic bromination, which continues to be an area of focus in synthetic chemistry because aryl bromides are very useful intermediates in the production of drugs, pharmaceuticals, agrochemicals, pigments, photographic materials, and various functional natural products [1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37]. This makes the development of regioselective electrophilic aromatic brominations a high priority.…”

“…Tetraalkylammonium tribromides are highly para -selective for bromination of phenols [12]. LDH-CO 3 2− -Br 3 − can be used for para -selective monobromination of some aromatic compounds [13]. Zeolites induce high para -selectivity for electrophilic bromination of substrates akin to toluene [14,15,16,17,18,19,20,21,22].…”