Tris(hydroxymethyl)phosphine
Trisphosphine is the organophosphorus compound with the formula P3. It is a white solid. The compound is multifunctional, consisting of three alcohol functional groups and a tertiary phosphine. It is prepared by treating tetrakis(hydroxymethyl)phosphonium chloride with strong base:
The compound can be prepared on a large scale using triethylamine as base and as solvent.
Reactions
The compound forms complexes with a variety of metals. These complexes display some solubility in water but more so in methanol.The compound decomposes violently to phosphine and formaldehyde upon attempted distillation. In air, it oxidizes to the oxide.
Upon heating with hexamethylenetetramine, it converts to the water-soluble ligand 1,3,5-triaza-7-phosphaadamantane.
Trisphosphine can also be used to synthesize the heterocycle, N-Boc-3-pyrroline by ring-closing metathesis using Grubbs' catalyst. N-Boc-diallylamine is treated with Grubbs' catalyst, followed by trisphosphine. The carbon-carbon double bonds undergo ring closure, releasing ethene gas, resulting in N-Boc-3-pyrroline.
The hydroxymethyl groups on THPC undergo replacement reactions when THPC is treated with α,β-unsaturated nitrile, acid, amide and epoxides. For example, base induces condensation between THPC and acrylamide with displacement of the hydroxymethyl groups.
Similar reactions occur when THPC is treated with acrylic acid; only one hydroxymethyl group is displaced, however.