Diastereoselective Hydroxymethylation of Cyclic <i>N</i>-<i>tert</i>-Butanesulfinylketimines Using Methoxymethanol as Formaldehyde Source

Hydroxymethylation of cyclic <i>tert</i>-butanesulfinylketimine-derived lithium enamides with methoxymethanol proceeds with excellent diastereoselectivity (99:1 dr). Methoxymethanol is a stable and easy-to-handle source of anhydrous monomeric formaldehyde in the reaction with lithium enamides. Cyclic α-hydroxymethyl ketimines undergo highly diastereoselective reduction to <i>syn</i>- or <i>anti</i>-1,3-amino alcohols