(1 S *,4 S *,5 R *,8 R *)‐8‐(3,4‐Dimethoxyphenyl)‐4‐(3,4,5‐trimethoxyphenyl)‐3,7‐dioxabicyclo[3.3.0]octan‐2‐one

The X‐ray study of the title compound, C 23 H 26 O 8 , (I), confirmed the endo,exo ‐furofuranone structure of the important intermediate compound in the process of the total synthesis of (±)‐epimagnolin A, which employs a new approach involving a highly diastereoselective C—H insertion reaction [Brown et al. (2001). Tetrahedron Lett . 42 , 473–475].