The antituberculosis, antitumor, multibranched dodecafuranoarabinan of Mycobacterium species has been assembled from a single n-pentenylfuranoside source.

An n-pentenyl furanosyl-1,2-orthoester can function as a donor or be rearranged leading to an n-pentenyl furanoside acceptor which is glycosylated by its progenitor, regioselectively or doubly, thereby enabling rapid fabrication of a multibranched dodecasaccharide, known to possess a wide variety of biological interactions.