Premium
Bismuth(III) Trifluoromethanesulfonate: A Chameleon Catalyst for the Friedel–Crafts Acylation
Author(s) -
Répichet Sigrid,
Le Roux Christophe,
Dubac Jacques,
Desmurs JeanRoger
Publication year - 1998
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/(sici)1099-0690(199812)1998:12<2743::aid-ejoc2743>3.0.co;2-a
Subject(s) - chemistry , chlorobenzene , trifluoromethanesulfonate , toluene , benzene , acylation , friedel–crafts reaction , catalysis , reagent , organic chemistry , lewis acids and bases , bismuth , electrophilic aromatic substitution , medicinal chemistry
A mechanism for acylations catalyzed by bismuth(III) triflate ( 1 ) is proposed in the case of the benzoylation of benzene, toluene, and chlorobenzene. With Bz 2 O as a reagent, 1 acts as a Lewis acid and allows the benzoylation of toluene. It is almost completely recovered after the reaction. With BzCl, 1 promotes an exchange reaction which generates BzOTf, which is the active species of the benzoylation. In this latter case, the reaction leads to the formation of TfOH which finally reacts with BiCl 3 to partially regenerate 1 . The power of the Bz 2 O/ 1 system is less than that of BzCl/ 1 , which allows not only the benzoylation of toluene but also that of benzene and deactivated chlorobenzene. The activity of 1 is much higher than that of other metallic triflates previously reported, and is comparable with that of TfOH, however it also has the advantage that the triflate moieties are more easily recoverable.