Electroreduction of Triphenylphosphine
Oxide to Triphenylphosphine in the Presence of Chlorotrimethylsilane

Hiromu Kawakubo; Manabu Kuroboshi; Tomotake Yano; Kazuma Kobayashi; Syogo Kamenoue; Tomomi Akagi; Hideo Tanaka

doi:10.1055/s-0031-1289612

PAPER

Electroreduction of Triphenylphosphine Oxide to Triphenylphosphine in the Presence of Chlorotrimethylsilane

Hiromu Kawakubo^a, Manabu Kuroboshi*^b, Tomotake Yano^b, Kazuma Kobayashi^b, Syogo Kamenoue^b, Tomomi Akagi^b, Hideo Tanaka*^b
^a API Department, Asahi Kasei Chemicals Corporation, Kanda Jinbocho 1-105, Chiyoda-ku, Tokyo 101-8101, Japan
^b The Graduate School of Natural Science and Technology, Okayama University, Tsushima-Naka 3-1-1, Okayama 700-8530, Japan
Fax: +81(86)2518079; e-Mail: tanaka95@cc.okayama-u.ac.jp;

Abstract

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Abstract

Electroreduction of triphenylphosphine oxide to triphenylphosphine in an acetonitrile solution of tetrabutylammonium bromide in the presence of chlorotrimethylsilane was performed successfully in an undivided cell fitted with a zinc anode and a platinum cathode under constant current. A plausible mechanism involving, (1) one-electron reduction of triphenylphosphine oxide generating the corresponding anion radical [Ph₃P^˙ -O^-], (2) subsequent reaction with chlorotrimethylsilane affording the (trimethylsiloxy)triphenylphosphorus radical [Ph₃P^˙ -OSiMe₃], and (3) further one-electron reduction followed by P-O bond fission leading to triphenylphosphine is proposed. In a similar manner, electroreduction of some triarylphosphine oxides and alkyldiarylphosphine oxides was executed to give the corresponding phosphine derivatives in good to moderate yields.

Key words

reduction - electron transfer - phosphorus - silicon

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References

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