Efficient acetalisation of aldehydes catalyzed by titanium tetrachloride in a basic medium

Article abstract of DOI:10.1016/S0040-4020(98)00982-X

The acetalisation of aliphatic and aromatic aldehydes is achieved in a basic medium by using catalytic amount of Ti(IV) chloride in MeOH in the presence of NH₃ or Et₃N. The present protocol shows many advantages over the well known base or acid catalysis: in fact, in contrast to base-promoted acetalisation, aldehydes with electron-rich carbonyl groups react easily, enolizable aldehydes do not undergo aldol condensation and, in contrast to acid-catalysis, migration of the double bond does not occur in the preparation of α,β-unsaturated acetals.