We report the concise synthesis of (+)-polyoxamic acid and (+)-5-O-carbamoyl polyoxamic acid from L-xylose in seven or six steps, respectively. The key steps include a diastereoselectiveamination of syn-1,2-polybenzyl ethers usingchlorosulfonylisocyanate (CSI) and the one-pot introduction of carbamates into the allylic benzyl ether and primary hydroxyl moieties.