Radical Hydrophosphination Initiated by Triamidoamine-Supported Titanium Despite Insertion into the Ti–P Bond

25 January 2023, Version 1
This content is a preprint and has not undergone peer review at the time of posting.

Abstract

Titanium compounds supported by the triamidoamine ligand (N3N, N(CH2CH2NSiMe33–)3) have been investigated for hydrophos-phination catalysis. The simple titanium alkyl compound (N3N)TiMe (2) demonstrate modest activity as a precatalyst for the pho-tocatalytic hydrophosphination of styrene, but the terminal phosphido compound, (N3N)TiPHPh (4), is inactive. Analysis of these reactions by EPR spectroscopy indicates that (N3N)TiMe undergoes homolytic Ti–C bond cleavage to achieve radical hydrophos-phination. This pathway was further supported in a radical trapping experiment. The phosphido derivative 4 does not produce rad-icals under similar conditions, despite undergoing facile migratory insertion reactions with polar substrates featuring C–N and C–O multiple bonds. Both nitrile and isonitrile substrates insert with ultimate formation of phosphaalkene products, a change in reactivi-ty as comparted to the zirconium congener. Molecular structures of (N3N)TiPHPh (4), (N3N)TiNBnC=PPh (5), and (N3N)TiN(H)C(Ph)=PPh (6) are reported.

Keywords

hydrophosphination
titanium
phosphine
photocatalysis
radical
insertion

Supplementary materials

Title
Description
Actions
Title
Supporting Information
Description
spectra associated with the study
Actions

Comments

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.