Cobaloxime Catalysis: Selective Synthesis of Alkenylphosphine Oxides under Visible Light
- 11 August 2019
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 141 (35), 13941-13947
- https://doi.org/10.1021/jacs.9b06920
Abstract
Direct activation of H-phosphine oxide to react with an unsaturated carbon-carbon bond is a straightforward approach for accessing alkenylphosphine oxides, which shows significant applications in both synthetic and material fields. However, expensive metals and strong oxidants are typically required to realize the transformation. Here, we demonstrate the utility of earth-abundant cobaloxime to convert H-phosphine oxide into its reactive radical species under visible light irradiation. The radical species thus generated can be utilized to functionalize alkenes and alkynes without any external photosensitizer and oxidant. The coupling with terminal alkene generates E-alkenylphosphine oxide with excellent chemo- and stereoselectivity. The reaction with terminal alkyne yields linear E-alkenylphosphine oxide via neutral radical addition, while addition with internal ones generates cyclic benzophosphine oxides and hydrogen. Mechanistic studies on radical trapping experiments, electron spin resonance studies, and spectroscopic measurements confirm the formation of phosphinoyl radical and cobalt intermediates that are from capturing the electron and proton eliminated from H-phosphine oxide. The highlight of our mechanistic investigation is the dual role played by cobaloxime, viz., both as the visible light absorber to activate the P(O)-H bond as well as a hydrogen transfer agent to influence the reaction pathway. This synergetic feature of the cobaloxime catalyst preforming multiple functions under ambient condition provides a convergent synthetic approach to vinylphosphine oxides directly from H-phosphine oxides and alkenes (or alkynes).Funding Information
- Ministry of Science and Technology of the People's Republic of China (2017YFA0206903)
- National Natural Science Foundation of China (21861132004)
- Chinese Academy of Sciences (XDB17000000, QYZDY-SSW-JSC029, 2018VCA0001)
- K. C. Wong Education Foundation
This publication has 49 references indexed in Scilit:
- Catalyst‐ and Oxidant‐Free Desulfonative C−P Couplings for the Synthesis of Phosphine Oxides and PhosphonatesAdvanced Synthesis & Catalysis, 2017
- Highly Selective Phosphinylphosphination of Alkenes with Tetraphenyldiphosphine MonoxideAngewandte Chemie, 2016
- Intramolecular, Pd/Cu-Co-catalyzed P–C Bond Cleavage and Addition onto an Alkyne: A Route to BenzophospholesOrganic Letters, 2015
- Silver-Mediated Oxidative C–H/P–H Functionalization: An Efficient Route for the Synthesis of Benzo[b]phosphole OxidesJournal of the American Chemical Society, 2013
- An Approach to Benzophosphole Oxides through Silver‐ or Manganese‐Mediated Dehydrogenative Annulation Involving C-C and C-P Bond FormationAngewandte Chemie, 2013
- Phosphinate Chemistry in the 21st Century: A Viable Alternative to the Use of Phosphorus Trichloride in Organophosphorus Synthesis.Accounts of Chemical Research, 2013
- Pd(II)-Catalyzed Phosphorylation of Aryl C–H BondsJournal of the American Chemical Society, 2013
- Direct Annulations toward Phosphorylated Oxindoles: Silver‐Catalyzed Carbon‐Phosphorus Functionalization of AlkenesAngewandte Chemie, 2013
- Organophosphorus π-Conjugated MaterialsChemical Reviews, 2006
- Synthetic Methods for Azaheterocyclic Phosphonates and Their Biological ActivityChemical Reviews, 2004