An enantio- and diastereocontrolledsynthesis of two monoterpenes having a 2,8-dioxabicyclo[3.3.1]nonane framework, (-)-semburin and (-)-isosemburin, isolated from Swertia japonica, has been developed starting from the chiral building block having a 7,8-dioxabicyclo[3.2.1]octane framework.