Extremely Fast P – C Bond Formation Using Ruthenium

Date

2022-06-29

Authors

Kellinghusen, Alexis

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Abstract

This project is part of ongoing research of a Cp*Ru hydrophosphination catalyst, Ru(5-Cp*)(PPh2)(PPh2H)2, in the Rosenberg group. This catalyst performs rapid regioselective hydrophosphination producing product phosphines in an atom economic process. The previously studied indenyl Ru catalyst had a turnover frequency (TOF) of 7 h-1 (at 90% conversion), whereas this new Cp*Ru catalyst has a TOF of 250 h-1 (at 90% conversion). Objectives of this project included exploring the phosphine and alkene scope involved in catalysis, the catalyst resting state and determining catalytic activity. The Cp*Ru catalyst was generated successfully with phosphines: PTolp2H, PEt2H and PCy2H. Only phosphines with sufficiently acidic P-H groups participated in catalysis due to the proposed turnover limiting step of the mechanism involving an intramolecular proton transfer step. Different alkenes were tested for participation in catalysis; only activated alkenes were found to participate. Understanding the substrate scope and catalyst resting state provides valuable insight and further evidence to support the proposed mechanism which is central for future catalyst design.

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Keywords

chemistry, ruthenium, catalyst, catalysis, hydrophosphination, phosphorus, carbon, substrate scope, mechanism

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