Organic Syntheses Using Gold’s Reagent

An iminium salt shown as structure 1 is named Gold’s reagent and its synthetic applications with various nucleophiles have been reported. The reactions of 1 with active methylene compounds or aniline derivatives are carried out under basic conditions and the condensed compounds such as β-dimethylaminomethylenes and amidine derivatives are formed. These synthetic processes can be applied to intramolecular cyclization and 5- or 6-membered heterocyclic rings are successfully synthesized from dinucleophiles. 1 can be also used as a formylating reagent because aldehydes are generated by the reaction of 1 with Grignard reagents and the consequent acid-catalyzed hydrolysis.