Fig. 3.

Flowchart of the standardized AGA process including purification and process feedback. Full forward arrows reflect the AGA process, synthesis (black) and analysis (blue), while thin backward arrows represent the various feedback levels. (I) Preautomated step is designed with standard building blocks, linker, and module system cycles (red box). (II) Automated synthesis with UV analysis provides the first-level feedback that reflects mostly on the success of glycosylation conversions (green box). (III) Following cleavage and partial deprotection, HPLC, MS, and NMR analysis of the crude products provides a second-level feedback reflecting on the conversion success and on the stereo- and regioselectivity (blue box). (IV) After global deprotection HPLC, IM-MS, and NMR analysis provides third-level feedback that reflects on the overall process including isolated yields (black box). Using the combination of the three levels of feedback, an optimized protocol is produced in minimum effort to allow for the reproducible synthesis of a single-entity oligosaccharide (magenta boxes).