Synthese Et Structure d'OXYDES Et Dioxydes De Phosphines Tertiaires

Platzer, N.; Dardoise, Francois; Bergeret, W.; Gautier, J C; Raynal, Serge

doi:10.1080/03086648608072780

Cited by 4 publications

(1 citation statement)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We began by studying the reaction of secondary phosphine oxides (SPOs) with alkyl halide electrophiles to form a P–C bond (yielding tertiary phosphine oxides), which is currently a poorly developed area of chemistry. Most known transformations of SPOs with electrophiles use aryl phosphine oxide nucleophiles and carbonyl electrophiles. − Reports of dialkyl SPOs reacting with alkyl electrophiles to form P–C bonds are both exceedingly rare and narrow in scope. − …”

Section: Introductionmentioning

confidence: 99%

Improved Synthetic Route to Heteroleptic Alkylphosphine Oxides

2017

View full text Add to dashboard Cite

A new method for the synthesis of heteroleptic alkylphosphine oxides (R 2 R 1 PO, where R ≠ R 1 ) from secondary phosphine oxides (or SPOs, R 2 HPO) is presented. These reactions were fast at room temperature, sterically selective, high yielding, and >95% pure after an aqueous wash. Deprotonation of an SPO generates a phosphinite anion ([R 2 P− O] − ) that was found to be highly selective for nucleophilic P−C bond formation (as opposed to O−C bond formation) with alkyl halides. Surprisingly, most strong organometallic bases failed to deprotonate SPOs to their respective phosphinite anions (pK a s for most SPOs are <27). Only sodium bis(trimethylsilyl)amide (NaHMDS) cleanly formed the phosphinite anion, which was stable in solution (0.1 M, 23 °C in THF) for over 24 h. The need for a very specific base to deprotonate suggests that both ion pairing and the conjugate acid play a role in stabilizing the phosphinite anion. Phosphinite anion reactivity followed the expected trend for an S N 2 mechanism on reaction with alkyl halides; elimination products were never observed. A wide variety of heteroleptic alkylphosphine oxides were isolated in near-quantitative yield with only an aqueous wash as purification. This methodology was then used to make new bis(phosphine oxide)alkanes and unsymmetrical α,ω-bis(phosphine oxide)alkanes (R 2 P(O)(CH 2 ) 3 P(O)R 12 ) on the benchtop with unprecedented ease.

show abstract