Tyramine Derivatives Catalyze the Aldol Dimerization of Butyraldehyde in the Presence of Escherichia coli.

Biogenic amine organocatalysts have transformed the field of synthetic organic chemistry. Yet despite their use in synthesis and to label biomolecules in vitro, amine organocatalysis in vivo has received comparatively little attention - despite the potential of such reactions to be interfaced with living cells and to modify cellular metabolites. Herein we report that biogenic amines derived from L-tyrosine catalyze the self-aldol condensation of butanal to 2-ethylhexenal - a key intermediate in the production of the bulk chemical 2-ethylhexanol - in the presence of living Escherichia coli and outperform many amine organocatalysts currently used in synthetic organic chemistry. Furthermore, we demonstrate that cell lysate from E. coli and the prolific amine overproducer Corynebacterium glutamicum ATCC 13032 catalyze this reaction in vitro, demonstrating the potential for microbial metabolism to be used as a source of organocatalysts for biocompatible reactions in cells.