Alkaline cleavage reactions of tetraalkylphosphonium salts

Abstract

Several representative tetraalkylphosphonium salts have been decomposed with potassium hydroxide in 70% aqueous dimethyl sulfoxide, a solvent greatly enhancing the nucleophilic activity of the hydroxide ion. The effects of ring size of cyclic phosphonium salts on cleavage products and rates are clearly evident with ring opening paralleling ring strain. Alcohols have been discovered to accompany phosphine oxide formation, but no alkenes resulting from Hofmann elimination were observed to form. The role of pseudorotation of pentacovalent intermediates is discussed in light of experimental findings.(1) (a) For a summary of pertinent references, see K. L. Marsi,

Nucleophilic arylation with tetraarylphosphonium salts

“…The alkaline hydrolysis of phosphonium salts has been well-studied for the past decades 30 39 40 41 42 43 44 45 46 47 . As a third-order reaction (first order with respect to phosphonium salt, second order to hydroxide) 40 41 , the alkaline hydrolysis of tetraphenylphosphonium salt would lead to the formation of triphenylphosphine oxide (Ph 3 PO) (refs 46 , 48 ).…”

“…CsHCO 3 might gradually decompose into Cs 2 CO 3 , water and carbon dioxide at the reaction temperature. The generated CsOH would promote the subsequent arylation via an alkaline-hydrolysis path 30 39 40 41 42 43 44 45 46 47 . Nucleophilic addition of hydroxide to phosphorus and the subsequent pseudorotation generate intermediate C , deprotonation of which by CsOH gives an oxyanionic phosphorane D .…”

Protonation of Zwitterionic Manganese and Rhenium Phosphoniostyryl Complexes (η5‐C5H5)(CO)2M––C(+PR3)=C(H)Ph: Experimental and DFT Study

“…1 H, 13 C{ 1 H}, and 31 P{ 1 H} NMR spectra were recorded on Bruker Avance 300, Bruker Avance 400, and Bruker Avance 600 instruments at 25 °C and referenced to the residual deuterated solvent signals ( 1 H and 13 C NMR) and external 85 % H 3 PO 4 , respectively. Vinylidene complexes 1 25 and 2 26 and phosphanes PPh 2 Me,27 PPhMe 2 ,28 and PMe 3 29 were prepared according to literature procedures.…”

Protonation of manganese phosphonioallenyl complexes

“…Complex 1 was prepared according to the modified procedure of Kolobova et al [17]. PPh 2 Me [18], PPhMe 2 [19], PMe 3 [20], and 1-phenyl-propynol [21] were prepared according to known procedures. PPh 2 CH 2 PPh 2 , PPh 2 CH 2 CH 2 PPh 2 , and HBF 4 $OEt 2 were purchased from Aldrich and used as received.…”