Glycosidation, IX. Synthesis of functionalised acetals for coupling with monoclonal antibodies and other biopolymers

For coupling of acetal‐glycosides 3 and 4 of cytotoxic aldehydes with biopolymers for the selective treatment of cancer, acetals of type 5 or 6 , which bear a carboxylic ester function or an acylated amino group in the alcohol moiety, were prepared by reaction of aldehydes 7a–d and the trimethylsilyl ethers 8a–d in the presence of a catalytic amount of trimethylsilyl trifluoromethanesulfonate.