Related Experiment Video
Updated: May 8, 2026

Preparation and Reactivity of a Triphosphenium Bromide Salt: A Convenient and Stable Source of Phosphorus(I)
Published on: November 22, 2016
An unusually unstable ortho-phosphinophenol and its use to prepare benzoxaphospholes having enhanced air-stability
Shanshan Wu1, Nihal Deligonal, John D Protasiewicz
1Department of Chemistry, Case Western Reserve University, Cleveland, Ohio 44106, USA. protasiewicz@case.edu.
Abstract:
The primary phosphine 3,5-di-tert-butyl-2-phosphinophenol has been prepared and characterized. Oddly, the presence of a sterically demanding tert-butyl group adjacent to the PH2 centre renders the molecule very sensitive to loss of PH3 and formation of 3,5-di-tert-butyl-phenol in chloroform solutions in the presence of air. The process was catalyzed by HCl and dependent on the purity of CDCl3. Despite the instability of 3,5-di-tert-butyl-2-phosphinophenol, this material could be employed to produce a series of luminescent 2-R-4,6-di-tert-butyl-1,3-benzoxaphospholes having greater air stability than corresponding less bulky 2-R-1,3-benzoxaphospholes.
Related Concept Videos
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Electrophilic Aromatic Substitution: Fluorination and Iodination of Benzene
Hydrolysis of Chlorobenzene to Phenol: Dow Process
Acidity and Basicity of Alcohols and Phenols
Directing Effect of Substituents: ortho–para-Directing Groups
Aldehydes and Ketones to Alkenes: Wittig Reaction Mechanism
The reaction begins with the nucleophilic addition between a phosphorus ylide and the carbonyl compound. Due to its carbanionic character, phosphorus ylide acts as a strong nucleophile and attacks the electrophilic carbonyl group. This generates a charge-separated dipolar intermediate called betaine. The negatively charged oxygen atom and...
