The Vilsmeier reagents generated from tertiary and secondary aliphatic
and aromatic amides and trifluoromethanesulfonic anhydride (Tf2O) rea
cted with different nucleophiles (ROH, RSH, RNH2) affording the relati
ve iminium and amidinium salts. The former, stable at room temperature
, were easily transformed into the corresponding esters or O-alkyl thi
oesters by treatment with OK or SK. (C) 1998 Elsevier Science Ltd. All
rights reserved.