Anti-Markovnikov alkene oxidation by metal-oxo–mediated enzyme catalysis

Teaching an enzyme to switch sites There has been a recent flurry of activity in modifying enzymes to conduct unnatural chemical reactions more cleanly or selectively than synthetic chemical catalysts. Hammer et al. now report application of a cytochrome P450 variant to an oxidation that has largely eluded efficient catalysis. They used directed evolution to mutate the enzyme so that it placed oxygen at the less substituted carbon of the C=C double bond in styrenes, forming aldehyde products. They thereby attained opposite site selectivity to that of the widely used palladium-catalyzed Wacker-Tsuji oxidation. Science , this issue p. 215