Application of Flow Chemistry to the Selective Reduction of Esters to Aldehydes

The reduction of esters to aldehydes is an important transformation in organic chemistry and several reducing agents have been described. However, the use of this reaction in medicinal and natural product chemistry is limited due to the instability of the intermediates and the high reactivity of the reaction products. In the current article, the general and selective reduction of esters with diisobutyl‐tert‐butoxyaluminum hydride in flow is reported. This reagent allows esters to be reduced in the presence of different functional groups, including those considered to be of similar or higher reactivity. Reduction of esters to aldehydes is an important transformation in organic chemistry. In the current article we disclose the application of diisobutyl‐tert‐butoxyaluminum hydride to reduce esters in a general and selective way.