Total synthesis of (±)-epithienamycins A and B [(±)-olivanic acids MM22380 and MM22382] and derivatives

(±)-(3R*,4R*)-4-(2,2-Dimethoxyethyl)-3[(1S*)-1-hydroxyethyl]azetidin-2-one (7), which has been stereoselectively synthesised via the 4-methoxycarbonylisoxazoline (4), was converted into (±)-epithienamycins A (2) and B (3)[(±)-olivanic acids MM22380 and MM22382], (±)-deacetylepithienamycin A (20), and the 2-phenylthio-substituted compound (19). This total synthesis confirms the relative stereochemistry of the natural antibiotics.