A chiron approach to the total synthesis of (+)-aculeatin D

A synthesis of natural aculeatin D has been achieved, with the key stereogenic centers taken from inexpensive and readily available D-xylose. In elaboration Of D-Xylose into a desired form readily applicable in synthesis a previously misinterpreted and overlooked abnormal selectivity in hydroxyl protection was noticed and exploited. Protocols were developed for monotosylation of a triol insoluble in CH2Cl2, and freezing the less stable isomer (aculeatin D) at the PIFA-mediated oxidative spirocyclization, respectively. An unexplained deprotonation at a benzyl protecting group by a thermodynamically more stable dithiane carbanion in the literature was also addressed.