Synthesis and structures of EOM-protected 2,6-bis(diphenylphosphino)-4-methylphenol and its deprotected P-chalcogenides, 2,6-bis(Ph₂P = E)-4-methylphenols (E = O, S, Se)

Abstract

Ethoxymethyl (EOM) group was used to protect the phenol functionality on 2,6-dibromo-4-methylphenol. Subjecting the protected phenol to n-butyllithium followed by reaction with chlorodiphenylphosphine produced 2,6-bis(diphenylphosphino)-4-methyl-ethoxymethylphenol (1). Reactions of 1 with H₂O₂, S₈ and Se (grey) followed by treatment with HCl led to isolation of 2,6-bis(diphenylphosphinyl)-4-methylphenol (3a), 2,6-bis(diphenylphosphinothioyl)-4-methylphenol (3b), and 2,6-bis(diphenylphosphinoselenoyl)-4-methylphenol (3c). Compounds 1 and 3a–b were fully characterized by multinuclear NMR and high-resolution mass spectrometry. In addition, compounds 1, 3a·(HOO)₂C(CH₃)₂, 3b, and 3c were characterized by single crystal X-ray diffraction experiments.

Graphical Abstract

Keywords:

• 2,6-Bis(phosphino)phenol
• phosphinyl
• phosphinothioyl
• phospinoselenoyl
• 2,2-di(hydroperoxy)propane

Acknowledgments

We are grateful to Dr. Warren Wood (University of Portland) for his help with NMR measurements.

Disclosure Statement

The authors declare no conflicts of interest regarding this article.

Additional information

Funding

Mass-spectrometry. This work was supported by Northern Illinois University’s Molecular Analysis Core which was established with support from Shimadzu Scientific Instruments. Material presented in this paper is based upon work supported by the National Science Foundation under Grant No. 1726931. X-ray diffraction. We acknowledge NSF-MRI Grant 0604188 for acquisition of X-ray diffractometer. General support. Experimental work presented in this paper was supported by University of Portland.