Selective Mixed Tishchenko Reaction via Substituted 4-Hydroxy-1,3-Dioxanes

Monoesters of 1,3-diols can be prepared with the mixed Tishchenko reaction from â-hydroxy aldehydes and another aldehyde. These two aldehydes form a diastereomeric mixture of 1,3-dioxan-4-ol hemiacetal derivatives which can be further converted to monoesters with suitable catalysts. Limitations in the formation and esterification of this hemiacetal intermediate have been investigated in this work and the formation and stability of 1,3-dioxan-4-ols was found to be aldehyde-, temperature-, and solvent-dependent. A new method was developed for selective preparation of monoesters of 1,3-diols with this mixed Tishchenko reaction via 1,3-dioxan-4-ols without any significant side products. During the development of this method a possibility to scale up the reactions to reach a selective and economical process was one of the main targets in this work.