Four-step convergent synthesis of trans-fused tetracyclic oxane

Four-step convergent synthesis of trans-fused tetracyclic oxane starting from monocyclic ethereal acetylene and triflate segments was achieved, which involved the following sequence: (i) connection of two monocyclic segments; (ii) oxidative formation of α-diketone; (iii) construction of trans-fused tetracyclic diacetal; and (iv) reductive etherification of the diacetal.