Stereoselective reductive rearrangement of alpha-hydroxy epoxides: A new method for synthesis of 1,3-diols

A novel and short synthetic method for the stereoselective synthesis of 1,3 -diols has been developed by an unusual reductive rearrangement of a series of cl-hydroxy epoxides with aluminum isopropoxide. The reaction process wa s also investigated with deuterium-labeled aluminum isopropoxide, which rev ealed a site-specific 1,2-carbon-to-carbon migration and successive stereos elective hydride shift. The main synthetically valuable feature is that up to three contiguous carbon centers, the C-1, C-2, and C-3, were stereoselec tively controlled with C-2 being quaternary. This reaction is of particular importance to the synthesis of newly developed powerful asymmetric hydroge nation catalysts containing the chiral ligands of spirocyclic diols.