Transeterification of the Intermediate Chloro-ester Compounds in the Sequence for Obtaining Corey Aldehyde Protected as Cyclic Acetals

Transesterification of the TBDMS-bis-protected compounds 10-1a and 10-2a with K2CO3 in methanol takes place with the cleavage of the secondary TBDMS group to compounds 13-1 and 13-2. The same compounds were obtained as proof of the transesterification of the bis-benzoate compounds 10-1b and 10-2b. In case of bis-THP protected compounds 10-1c and 10-2c, the secondary THP group, stable in base conditions, was expected not to be removed in transesterification conditions, resulting the compounds rezultind compusii 13-1c and 13-2c.