Described is the combination of microreactors and fluorous phase chemistry to assemble oligosaccharides. The synthesis of a -(1→6) linked d-glucopyranoside homotetramer serves to illustrate this approach. Glycosylations employing a Fmoc-protected glucosyl phosphate building block were performed in a silicon-based micro-structured device to optimize reaction conditions and for reaction scale-up. A perfluorinated linker at the reducing end of the oligosaccharides allowed for purification by fluorous solid-phase extraction (FSPE) and further functionalization. [ABSTRACT FROM AUTHOR]