The present study illustrates the possibility of a rational approach that bypasses the requirement for stoichiometric amounts of toxic oxidants and metal additives (including reagents and catalysts) in organic redox reactions. We describe an aziridination process that delivers a nitrene functionality to olefins from a readily available N-aminophthalimide. Remarkably, both electron-rich and electron-poor olefins are converted to aziridines with high efficiency. The continuum of applied potentials and the heterogeneous nature of reactions at electrode surfaces allow for the electrochemical discrimination of substrates which have similar redox potentials and therefore cannot be selectively reduced or oxidized using soluble reagents. This selectivity is due to the phenomenon of overpotential, the kinetic inhibition of electron transfer on a particular electrode surface.

No abstract

The spatially addressable electrolysis platform (SAEP) has been designed and constructed. It is demonstrated that the advantages of electrochemistry can be readily adapted to combinatorial chemistry and parallel synthesis formats. Parallel electrosynthesis of alpha-alkoxycarbamates, alpha-alkoxyamides, and alpha-alkoxysulfonamides via anodic oxidation of carbamates, amides, and sulfonamides, respectively, highlights the main features of the SAEP.

[reaction: see text] A novel electrochemical sulfoxide imination process is described. Our approach starts with a highly selective nitrene transfer from N-aminophthalimide to a variety of sulfoxides. This oxidative treatment is followed by reductive N-N bond cleavage under the controlled current conditions, which leads to a range of parent NH sulfoximines. In addition to solving the challenging problem of removing the N-phthalimido group, the overall process avoids the use of toxic oxidants and metal additives.

An electrochemical strategy for running nitrogen-transfer reactions on chemically inert anode surfaces has been developed. The generation and trapping of highly reactive nitrene-transfer reagents can be accomplished under mild conditions on platinum electrodes. The key factor that accounts for the high levels of chemoselectivity in this process is the phenomenon of overpotential. We have found that molecules that are similar in terms of propensity toward oxidation can be differentiated on the basis of their affinity to a given electrode surface. Thereby, reactive species can be selectively generated in the presence of acceptor molecules of interest. Specifically, a wide range of structurally dissimilar olefins can be transformed into the corresponding aziridines in the presence of N-aminophthalimide. Likewise, nitrene generation in the presence of sulfoxides leads to their chemoselective transformation into the corresponding sulfoximines. In this paper we discuss the underlying mechanistic foundation of these reactions.