36917-36-9Relevant articles and documents
ACYLATION D'ALCENES DANS LE SYSTEME ACYLANT ACIDE TRIFLUOROMETHANESULFONIQUE-HALOGENURE D'ACIDE
Roussel, Christian,Rajoharison, Harivelo G.,Metzger, Jacques
, p. 613 - 618 (2007/10/03)
The diacylation of 2-methyl-2-pentene and of related alcoholic precursors with trifluoromethanesulphonic acid/acetyl chloride was investigated. The initially formed pyrylium salts were converted directly into the corresponding pyridines. The influence of the reaction conditions (temperature; molar ratios AcCl/F3CSO3H/alkene; experimental procedure) was thoroughly examined permitting the observation of new aspects for the examined synthesis of pyrylium salts e.g.: a) formation of less substituted pyrylium salts 2 up to 94 percent selectivity; b) direct access to isomeric pyrylium salts 1 and 2 depending on the reaction conditions; c) formation of triacylation products 3, 4 which could be suppressed in favour of 2. The described procedure presents also experimental advantages (no crackings; easily tractable reaction mixtures).