Collect. Czech. Chem. Commun. 1999, 64, 119-129

Unexpected Course of the Reaction of 1,3-Bis(dimethylamino)trimethinium Perchlorate with 3-Substituted Prop-2-ynals Leading to 1-Aryl-2,4,6-triformylbenzenes

Petr Suchý, Dalimil Dvořák* and Martina Havelková

Department of Organic Chemistry, Prague Institute of Chemical Technology, Technická 5, 166 28 Prague 6, Czech Republic


Reaction of 1,3-bis(dimethylamino)trimethinium perchlorate (1) with 3-substituted prop-2-ynals (4) in acetic anhydride at the presence of ZnBr2 gives upon hydrolysis 1-substituted 2,4,6-triformylbenzenes (6) in low to moderate yield. This reaction is restricted to prop-2-ynals bearing electron rich aromatic substituents at the 3-position.

Keywords: Trimethinium salts; Prop-2-ynals; Triformylbenzenes; Biaryls; Benzene ring construction; Cyclization.