Easy synthesis of heterocyclic carbene complexes by activation of chalcogenopyrones and benzopyrones to pyrylium salts and subsequent addition of carbanion of methoxy(methyl)pentacarbonyltungsten carbene complex

Methylenechalcogenopyran and benzopyran Fischer carbene complexes are easily obtained from commercially available chalcogenopyrones or benzopyrones and carbanion of methoxy(methyl)carbene tungsten complex. The key of the heterocyclic carbene formation is the activation of the carbonyl group by alkylation with alkyl trifluoromethanesulfonate reagent.

Graphical abstractMethylenechalcogenopyran and benzopyran Fischer carbene complexes are obtained from commercially available chalcogenopyrones and benzopyrones and carbanion of methoxy(methyl)pentacarbonyl tungsten carbene complex. Activation of the carbonyl group by CH3SO3CF3 is the key of the carbene formation.Figure optionsDownload full-size imageDownload as PowerPoint slide