Enzyme-Catalyzed Carbonyl Olefination by the E. coli Protein YfeX in the Absence of Phosphines

Graphical Abstract

Finding Wittig without Phosph-in: Triphenylphosphine-free carbonyl olefination can be achieved with the heme-containing E. coli protein YfeX by using diazo compounds. The reaction can also be performed under Wittig-analogue conditions with oxophiles. Whole-cell catalysis with overexpressed YfeX shows a product formation of 440 mg L⁻¹ in 1 h.

Abstract

The Wittig-type carbonyl olefination reaction has no biocatalytic equivalent. To build complex molecular scaffolds, however, C−C bond-forming reactions are pivotal for biobased economy and synthetic biology. The heme-containing E. coli protein YfeX was found to catalyze carbonyl olefination by reaction of benzaldehyde with ethyl diazoacetate under aerobic conditions in the absence of a triphenylphosphine oxophile. The reaction was performed in whole cells and showed a product formation of 440 mg L⁻¹ in 1 h. It was, moreover, shown that the reaction could be performed under Wittig-analogue conditions in the presence of triphenylphosphine or triphenylarsine.