An efficient 1,2-chelation-controlled reduction of protected hydroxy ketones via Red-Al.

In this paper, we have demonstrated that Red-Al is an efficient chelation-controlled reducing reagent for acyclic acetal (i.e., MOM, MEM, SEM, and BOM) protected alpha-hydroxy ketones. Typically, diastereomeric ratios (dr) ranged from 5 to 20:1 for the 1,2- anti-diols in good to excellent yields.