Issue 8, 1987

Electrochemical oxidation of 2,2,6,6-tetramethylpiperidines in acetonitrile: mechanism of N-cyanomethylation

Abstract

Electrochemical oxidation of 2,2,6,6-tetramethylpiperidine (1a), its 4-oxo derivative (1b), and 2,2,6,6-tetramethylmorpholine (1c) in deoxygenated acetonitrile gave the corresponding N-cyanomethylated products (2). The process was investigated by cyclic voltammetry, controlled-potential electrolysis, and electrolysis in the cavity of an e.s.r. spectrometer. The sequence of cyanomethylation is proposed to be as follows: one-electron transfer from (1) to generate the radical cation, [graphic omitted]H+˙(3); deprotonation of (3) to give the aminyl radical, [graphic omitted]: (4); hydrogen abstraction by (4) from the solvent to afford the cyanomethylene radical; cross-coupling of (4) with the solvent-derived radical. The generation of the radical (4) was confirmed by the e.s.r. experiments. The decay of the 4-oxopiperidinyl radical (4b) obeyed first-order kinetics and exhibited a large primary deuterium isotope effect in [2H3]acetonitrile, indicating that the hydrogen abstraction is rate-determining. The voltammetric behaviour of (1) in oxygen-saturated acetonitrile suggested that the aminyl radical (4) is oxidized at a potential more positive than is the starting amine (1).

Article information

Article type
Paper

J. Chem. Soc., Perkin Trans. 2, 1987, 1065-1069

Electrochemical oxidation of 2,2,6,6-tetramethylpiperidines in acetonitrile: mechanism of N-cyanomethylation

H. Ohmori, C. Ueda, K. Yamagata, M. Masui and H. Sayo, J. Chem. Soc., Perkin Trans. 2, 1987, 1065 DOI: 10.1039/P29870001065

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Spotlight

Advertisements