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Despite the wide utility of hydroxylamines in organic synthesis, relatively few are commercially available, and there is a need for direct, efficient, and selective methods for their synthesis. Herein, we report two complementary methods to accomplish direct oxidation of secondary amines using UHP as an oxidant. The first method uses 2,2,2-trifluoroethanol (TFE) and a large excess of amine. Isolation of hydroxylamine products is enabled by selective salt formation, and recovery of excess amine is demonstrated. The second method uses hexafluoroacetone as an additive and is highlighted by the 1:1 stoichiometry between the oxidant and amine.

While attempting to synthesize biaryl ethers we discovered the inadvertent formation of a methylsulfoxylmethyl ether byproduct. Formation of this unexpected byproduct presented an opportunity to streamline the synthesis of methylsulfoxylmethyl ethers. Mechanistic studies suggest a radical pathway with dimsyl potassium as a reducing agent.