Biocompatible α‐Methylenation of Metabolic Butyraldehyde in Living Bacteria

Abstract Small molecule organocatalysts are abundant in all living organisms. However, their use as organocatalysts in cells has been underexplored. Herein, we report that organocatalytic aldol chemistry can be interfaced with living Escherichia coli to enable the α‐methylenation of cellular aldehydes using biogenic amines such as L‐Pro or phosphate. The biocompatible reaction is mild and can be interfaced with butyraldehyde generated from D‐glucose via engineered metabolism to enable the production of 2‐methylenebutanal (2‐MB) and 2‐methylbutanal (2‐MBA) by anaerobic fermentation, and 2‐methylbutanol (2‐MBO) by whole‐cell catalysis. Overall, this study demonstrates the combination of non‐enzymatic organocatalytic and metabolic reactions in vivo for the sustainable synthesis of valuable non‐natural chemicals that cannot be accessed using enzymatic chemistry alone.