1. Electrochemical Azidooxygenation of Alkenes Mediated by a TEMPO-N 3 Charge-Transfer Complex.
- Author
-
Siu JC, Sauer GS, Saha A, Macey RL, Fu N, Chauviré T, Lancaster KM, and Lin S
- Subjects
- Chemistry Techniques, Synthetic, Electrochemical Techniques, Kinetics, Spectrophotometry, Ultraviolet, Azides chemistry, Cyclic N-Oxides chemistry
- Abstract
We report a mild and efficient electrochemical protocol to access a variety of vicinally C-O and C-N difunctionalized compounds from simple alkenes. Detailed mechanistic studies revealed a distinct reaction pathway from those previously reported for TEMPO-mediated reactions. In this mechanism, electrochemically generated oxoammonium ion facilitates the formation of azidyl radical via a charge-transfer complex with azide, TEMPO-N
3 . DFT calculations together with spectroscopic characterization provided a tentative structural assignment of this charge-transfer complex. Kinetic and kinetic isotopic effect studies revealed that reversible dissociation of TEMPO-N3 into TEMPO• and azidyl precedes the addition of these radicals across the alkene in the rate-determining step. The resulting azidooxygenated product could then be easily manipulated for further synthetic elaborations. The discovery of this new reaction pathway mediated by the TEMPO+ /TEMPO• redox couple may expand the scope of aminoxyl radical chemistry in synthetic contexts.- Published
- 2018
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