Mechanochemical Friedel–Crafts acylations

Abstract

Friedel–Crafts (FC) acylation reactions were exploited in the preparation of ketone-functionalized aromatics. Environmentally more friendly, solvent-free mechanochemical reaction conditions of this industrially important reaction were developed. Reaction parameters such as FC catalyst, time, ratio of reagents and milling support were studied to establish the optimal reaction conditions. The scope of the reaction was explored by employment of different aromatic hydrocarbons in conjunction with anhydrides and acylation reagents. It was shown that certain FC-reactive aromatics could be effectively functionalized by FC acylations carried out under ball-milling conditions without the presence of a solvent. The reaction mechanism was studied by in situ Raman and ex situ IR spectroscopy.

A fruitful century for the scalable synthesis and reactions of biphenyl derivatives: applications and biological aspects

“…112 Further, biphenyl-4-carbonyl-benzoic acid ( 91 ) was synthesized through free-solvent mechanochemical ball milling method via reaction of biphenyl ( 2 ) with phthalic anhydride in the presence of AlCl 3 . 113 Whereas, gaseous boron trifluoride (BF 3 ) was passed through a homogenous mixture of biphenyl ( 2 ) and acetic anhydride to synthesize biphenyl-4-yl-2,2-difluoro-6-methyl-dioxaborinine ( 92 ) (Scheme 38). 114…”

Recent Advances in Mechanochemical Organic Synthesis

“…Novel mechanochemical C▬C bond forming reactions include Friedel-Crafts acylation [34] and alkylation which was also employed in polymer synthesis [35]. Porphyrin synthesis in which mechanochemical procedure was reported earlier was extended to bulkier aromatics [36] and the solventless metalation of porphyrins [37,38].…”

The Mechanochemical Fries Rearrangement: Manipulating Isomer Ratios in the Synthesis of p‐Hydroxyacetophenone at Different Scales**

“…Due to its inherent solvent-free character, it is gaining increasing attention as a sustainable alternative to conventional solvent-based reactions. [12][13][14][15][16] Mechanochemistry has been used for the synthesis of a variety of compounds such as organic, [17][18][19][20] inorganic, [21] or polymer [22] materials and has demonstrated the potential of altering product selectivity and even accessing novel compounds. [23][24][25][26][27][28][29] In this context, the combination of mechanical and thermal energy and precise temperature control have emerged as important parameters in recent years.…”