Selective C–P(O) Bond Cleavage of Organophosphine Oxides by Sodium

Abstract

Sodium exhibits better efficacy and selectivity than Li and K for converting Ph3P­(O) to Ph2P­(OM). The destiny of PhNa co-generated is disclosed. A series of alkyl halides R4X and aryl halides ArX all react with Ph2P­(ONa) to produce the corresponding phosphine oxides in good to excellent yields.

Beyond Triphenylphosphine: Advances on the Utilization of Triphenylphosphine Oxide

“…Thus far, studies have been focused on the reduction of Ph 3 P­(O) to Ph 3 P that is also industrially used. Beyond Ph 3 P, Ph 3 P­(O) has been shown to be a highly valuable starting chemical for the preparation of other very useful organophosphorus compounds including diphenyl­(alkyl/aryl)­phosphine oxides, dialkyl­(phenyl)­phosphine oxides, trialkylphosphine oxide, diphenyl­(alkyl)­phosphines, dibenzophosphole (oxides), and triphenylphosphonium cations, etc. via selective P–C, P–O, or C–H bond cleavage.…”

“…No other side products could be detected at all. Ph 2 PONa could readily react with alkyl halides (Cl, Br, I), acyl chloride (MesCOCl), and aryl bromides (ArBr) to access the corresponding phosphine oxides Ph 2 P­(O)­R 1 with high efficiency (Scheme a) . By switching the conditions, when Ph 3 P­(O) reacted with PhNa (in situ prepared from 2.0 mmol SD with 1.1 mmol PhCl in hexane) at room temperature, sodium dibenzophosphole oxide ( B ) could be generated predominantly (up to 82% yield) (Scheme c) .…”

Low-Coordinate Magnesium Sulfide and Selenide Complexes

“…33,34 The generated NaPh has been shown to then react with the THF solvent to form sodium vinyl alkoxide in this system. 33,34 The relatively harsh reaction conditions for the formation of 3 and the color of the solution and the formation of biphenyl as the byproduct suggest that the reaction proceeds via donor adducts of magnesium(I) complexes with elongated Mg−Mg bonds [13][14][15]35 (e.g., Ph 3 PO bisadducts of 1) and could also point to the formation of radicals during the process. In contrast, reactions of Ph 3 P�E (E = S, Se) with 1, followed by NMR spectroscopy in deuterated benzene, proceeded very rapidly at room temperature, giving high in situ yields of the low-coordinate chalcogenide complexes [{( iPrDip NacNac)Mg} 2 (μ-S)] 4 and [{( iPrDip NacNac)Mg} 2 (μ-Se)] 5 (see Figures 3 and 4, respectively) and Ph 3 P (Scheme 1).…”

“…The addition of one equivalent of Ph 3 P�O to a yellow benzene-d 6 solution of 1 at ambient temperature showed no reaction as judged by 1 H and 31 P{ 1 H} NMR spectroscopy. 33,34 The generated NaPh has been shown to then react with the THF solvent to form sodium vinyl alkoxide in this system. 33,34 The relatively harsh reaction conditions for the formation of 3 and the color of the solution and the formation of biphenyl as the byproduct suggest that the reaction proceeds via donor adducts of magnesium(I) complexes with elongated Mg−Mg bonds [13][14][15]35 (e.g., Ph 3 PO bisadducts of 1) and could also point to the formation of radicals during the process.…”

Phosphafluorenyl lithiums: direct synthesis from white phosphorus, structure and diversified synthons

“…In contrast to the rich chemistry of phospholyl anions, phosphafluorenyl anions (Scheme 1-III) are only proposed as the critical intermediates for the synthesis of phosphafluorenes (dibenzophospholes) (Scheme 1-IV), which have a wide range of applications because they can serve as (1) suitable ligands in organometallic chemistry and organic synthesis methodology [11][12][13]; (2) organocatalysts in some classic organic reactions (e.g., Appel reaction, Staudinger reaction) [14,15]; and (3) organic optoelectronic materials [16][17][18][19]. Metalmediated P-C bond cleavage of Ph-substituted phosphafluorenes is the classic method for the in situ generation of phosphafluorenyl anions (e.g., lithium, sodium, potassium) (Scheme 2a) [20][21][22][23]. To the best of our knowledge, there is no report on the structural characterizations and the aggregation states of phosphafluorenyl anions.…”