Phosphine-catalysed reductive coupling of Dihalophosphanes

27 July 2021, Version 1
This content is a preprint and has not undergone peer review at the time of posting.


Classically, tetraorgano diphosphanes have been synthesized through Wurtz-type reductive coupling of halophosphanes R2PX or more recently, through the dehydrocoupling of phosphines R2PH. Catalytic variants of the dehydrocoupling reaction have been reported but are limited to R2PH compounds. Using PEt3 as a catalyst, we now show that TipPBr2 (Tip = 2,4,6-iPr3C6H2) is selectively coupled to give the dibromodiphosphane (TipPBr)2 (1), a compound not accessible using classic Mg reduction. Surprisingly, when using DipPBr2 (Dip = 2,6-iPr3C6H3) in the PEt3-catalysed reductive coupling the diphosphene (PDip)2 (2) with a P=P double was formed selectively. In benzene solutions (PDip)2 has a half life-time of ca. 28 days and can be utilized with NHCs to access NHC-phosphinidene adducts. Control experiments show that [BrPEt3]Br is a potential oxidation product in the catalytic cycle, which can be then debrominated by using Zn dust as sacrificial reductant.


Homogenous Catalysis
Reductive Coupling

Supplementary materials

Electronic Supporting Information
Electronic Supplementary Information (ESI) available: Synthesis and characterization of compounds, NMR and IR spectra, crystallographic, and computational details.


Comments are not moderated before they are posted, but they can be removed by the site moderators if they are found to be in contravention of our Commenting Policy [opens in a new tab] - please read this policy before you post. Comments should be used for scholarly discussion of the content in question. You can find more information about how to use the commenting feature here [opens in a new tab] .
This site is protected by reCAPTCHA and the Google Privacy Policy [opens in a new tab] and Terms of Service [opens in a new tab] apply.