Synthesis 2020; 52(23): 3583-3594
DOI: 10.1055/s-0040-1707345
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© Georg Thieme Verlag Stuttgart · New York

1,3-Diphenyldisiloxane Enables Additive-Free Redox Recycling Reactions and Catalysis with Triphenylphosphine

Joseph A. Buonomo
,
Malcolm S. Cole
,
Carter G. Eiden
,
Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN 55455, USA   Email: aldri015@umn.edu
› Author Affiliations
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Publication History

Received: 17 February 2020

Accepted after revision: 30 June 2020

Publication Date:
04 August 2020 (online)


Abstract

The recently reported chemoselective reduction of phosphine oxides with 1,3-diphenyldisiloxane (DPDS) has opened up the possibility of additive-free phosphine oxide reductions in catalytic systems. Herein we disclose the use of this new reducing agent as an enabler of phosphorus redox recycling in Wittig, Staudinger, and alcohol substitution reactions. DPDS was successfully utilized in ambient-temperature additive-free redox recycling variants of the Wittig olefination, Appel halogenation, and Staudinger reduction. Triphenylphosphine-promoted catalytic recycling reactions were also facilitated by DPDS. Additive-free triphenylphosphine-promoted catalytic Staudinger reductions could even be performed at ambient temperature due to the rapid nature of phosphinimine reduction, for which we characterized kinetic and thermodynamic parameters. These results demonstrate the utility of DPDS as an excellent reducing agent for the development of phosphorus redox recycling reactions.

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