A Modular Approach to the Total Synthesis of Tunicamycins

The tunicamycins constitute a delicate mimic of the bisubstrate intermediates of N-acetyl-D-hexosamine-1-phosphate translocases and thus inhibit bacterial cell-wall synthesis and the Nglycosylation of eukaryotic proteins. An efficient approach to the synthesis of this unique type of nucleoside antibiotics is now reported and features the assembly of five modules in a highly stereoselective and robust manner. A Mukaiyama aldol reaction, intramolecular acetal formation, gold(I)-catalyzed O and Nglycosylation, and final Nacylation were used as the key steps.