Selective mono-chlorination of aromatic compounds

Regioselective Electrophilic Aromatic Substitution Reactions over Reusable Zeolites

“…Furthermore, the reaction was shown to work for the preparation of para-chlorotoluene and para-dichlorobenzene on 0.1 mole scale without any detrimental effects on either the yield or the selectivity [159].…”

“…Furthermore, using tert-butyl hypochlorite over HX produced almost quantitative ring chlorination of toluene within one hour at 25 °C in tetrachloromethane as solvent (Scheme 16, X = Me) [159]. The fact that the reaction proceeded readily with zeolite HX as catalyst is consistent with the fact that faujasite has the largest pore diameter of all the zeolites tried and also has a three dimensional lattice structure with many interconnecting cavities of even greater dimensions, so that diffusion of substrate and reagents through the pores is relatively easy.…”

“…Some of the results obtained are recorded in Table 17. t OCl (2.5 mmol), HNaX (1.5 g) and solvent (10 ml) at 25 °C for the reaction time [159].…”

Microwave-Promoted Synthesis of 4-Arylpyrimidines by Pd-Catalysed Suzuki–Miyaura Coupling of 4-Pyrimidyl Tosylates in Water

“…4 The use of Lewis acids to promote these reactions frequently leads to non-negligible mixtures of regioisomers. 5 Although methods for the halogenation of arenes have been improved, 6 the best results are based on already functionalized starting materials. 7,8 Problems of regioselectivity 5b have been overcome in a few cases by careful selection of the arene system 9 or by using transition-metal catalysts.…”

Improved Regioselective Mononitration of o-Xylene over HBEA-500 Zeolite Catalyst

“…Smith and coworks have utilized zeolites to enhance the para-selectivity in chlorination, 8 acylation, 9 and methanesulfonylation 10 of simple aromatic substrates. The present investigation was to develop a mild, easy to operate and efficient catalyst [11][12][13][14] without involving sulfuric acid and some progress has been achieved.…”