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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. [ABSTRACT FROM AUTHOR]

The reduction of activated C=C double bonds is an important reaction in synthetic chemistry owing to the potential formation of up to two new stereogenic centers. Artificial nicotinamide cofactors were recently presented as alternative suppliers of hydride equivalents needed for alkene reduction. To study the effect of cofactors on the reduction of activated alkenes, a set of N-substituted synthetic nicotinamide cofactors with differing oxidation potentials were synthesized and their electrochemical and kinetic behavior was studied. The effects of the synthetic cofactors on enzyme activity of four ene reductases are outlined in this study, where the cofactor mimic with an N-substituted 4-hydroxy-phenyl residue led to a sixfold higher vmax relative to the natural cofactor NADH. [ABSTRACT FROM AUTHOR]

The Cover shows an enzymatic carbonyl olefination reaction in E.coli where the corresponding enzyme—depicted as the clownfish nemo—has to be found in the organism which is represented by the ocean. In their paper, Weissenborn, Löw et al. present a method to find new enzyme activities by utilizing an entire cell lysate with its thousands of proteins as catalyst. Once they found that the cell lysate catalyzes a carbonyl olefination reaction they determined, isolated, and studied the corresponding protein. The results show the first enzymatic carbonyl olefination in absence of phosphines, as well as the feasibility of the performed general approach in cell lysates. More information can be found in the Communication by Weissenborn, Löw et al. on page 1636 in Issue 9, 2016 (DOI: 10.1002/cctc.201600227). [ABSTRACT FROM AUTHOR]

The Cover shows a running track and three competing cofactors on their way to an enzyme. The goal is the flavin in the active side of the enzyme NADH‐dependent cyclohexenone reductase (NCR) from Zymomonas mobilis. Two of the three cofactors are artificial mimics presented in the Full Paper of S. Löw et al. Besides the electrochemical characterization of the mimics, the authors screened their activity with several enzymes and substrates. The NCR was found to be very efficient in utilizing cofactor mimics. Kinetic comparison of NADH and the mimic HPNAH with NCR and Z‐citral as a substrate revealed a sixfold higher vmax for HPNAH. This is indicated on the figure by HPNAH winning the race to the enzyme. More information can be found in the Full Paper by Löw et al. on page 911 in Issue 5, 2016 (DOI: 10.1002/cctc.201501230). [ABSTRACT FROM AUTHOR]