Abstract Dimethylaluminium methaneselenolate (Me 2 AlSeMe, 1) acts as an acyl transfer agent for esterification. In cases of direct macrolactonisation (n= 10–12), this selenium– aluminium complex preferentially creates symmetric macrodiolides rather than macrolides. The factors determining macrodilactonisation were investigated and applied toward the total synthesis of norpyrenophorin, which result in a macrodilactonisation yield of 64%.
