Abstract
Compared to the biological world's rich chemistry for functionalizing carbon, enzymatic transformations of the heavier homologue silicon are rare. We report that a wild‐type cytochrome P450 monooxygenase (P450BM3 from Bacillus megaterium, CYP102A1) has promiscuous activity for oxidation of hydrosilanes to give silanols. Directed evolution was applied to enhance this non‐native activity and create a highly efficient catalyst for selective silane oxidation under mild conditions with oxygen as the terminal oxidant. The evolved enzyme leaves C−H bonds present in the silane substrates untouched, and this biotransformation does not lead to disiloxane formation, a common problem in silanol syntheses. Computational studies reveal that catalysis proceeds through hydrogen atom ion followed by radical rebound, as observed in the native C−H hydroxylation mechanism of the P450 enzyme. This enzymatic silane oxidation extends nature's impressive catalytic repertoire.
In rerum natura: Wild‐type cytochrome P450BM3 catalyzes the oxidation of hydrosilanes to silanols both in vivo and in vitro. Directed evolution was used to generate an efficient and selective biocatalyst that delivers a broad range of aryl‐ and alkyl‐substituted silanols. Computational studies revealed a sequence of H atom ion and OH rebound as the mechanism, in analogy to the native C−H hydroxylation activity.