High-valent titanium(IV)salophen: An efficient catalyst for rapid conversion of aldehydes to 1,1-diacetates with acetic anhydride

In the present work, a mild and highly efficient method for protection of aldehydes with acetic anhydride in the presence of high-valent titanium (IV) salophen trifluoromethanesulfonate, [TiIV(salophen)(OTf)2], at room temperature is reported. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with acetic anhydride and the corresponding 1,1-diacetates were obtained in good to excellent yields. The results showed that the yields were higher for aldehydes bearing electron-withdrawing substituents such as nitro, chloro, bromo and 3-methoxy, while aldehydes containing electron donating groups such as 4-methoxy and 4-methyl produced the lower yields. The catalyst was reused several times without loss of its catalytic activity.

Graphical abstractA mild and highly efficient method for protection of aldehydes with acetic anhydride in the presence of high-valent [TiIV(salophen)(OTf)2] is reported. Under these conditions, different aldehydes bearing electron-withdrawing and electron-donating substituents were reacted with acetic anhydride and the corresponding 1,1-diacetates were obtained in good to excellent yield. The catalyst was reused several times without loss of its catalytic activity.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Electron-deficient Ti(IV)salophene was used as catalyst. ► 1,1-Diacetates were obtained by the reaction of aldehydes with acetic anhydride. ► The reaction was carried out at room temperature. ► The catalyst was reusable.