A formal synthesis of (+)-muricatacin from D-xylose

A multistep route towards the aldehydo-lactone 19, the final chiral precursor in a new stereospecific synthesis of (+)-muricatacin, has been developed starting from D-xylose. The key step of the synthesis involves an E-selective Wittig olefination of the lactol 6 with methoxycarbonylmethylidene triphenylphosphorane, followed by successive catalytic reduction and ?-lactonisation processes. Subsequent selective functional groups interconver- sions furnished the key six-carbon intermediate 19, which can be converted into the (+)-muricatacin via a three-step sequence already described in the chemical literature.