Oxidative Cleavage of Ketoximes to Ketones using Photoexcited Nitroarenes

Methoximes are a versatile directing group for a variety of C–H functionalizations. Despite their importance as a powerful functional handle, their conversion to the parent ketone, which is often desired, usually requires harsh and functional group intolerant reaction conditions that make their application in a late-stage context problematic. Here, we present an alternative set of conditions to achieve mild and functional group tolerant conversion of methoximes to the parent ketones using photoexcited nitroarenes. The utility of this methodology is showcased in its application in the total synthesis of cephanolide D. Furthermore, mechanistic insight into this transformation obtained using isotope labeling studies as well as the analysis of reaction byproducts is provided.