The utility of intramolecular glycosylation for the synthesis of the 27‐membered macrocyclic ring is highlighted in this first total synthesis of the most complex resin glycoside isolated to date – Calysolin IX. Oligosaccharide‐containing macrolides core was effectively constructed by TfOH/NIS‐promoted intramolecular glycosylation of thioglycosyl donor. As the glycosidic bond must be created en route to target structure, we show that this unusual yet efficient approach can effectively reduce the number of steps in the total synthesis of complex natural macrolides. This attempt is documented as an efficient tool in the synthesis of gigantic macrolide rings thus proving their practical utility in the total synthesis of sugar‐containing targets.