Phosphites/phosphonites

Sterically hindered phenols and other additives containing thioesters, phosphites, phosphonites and hindered amine moieties were analysed by FAB-MS and LD-FTMS. The laser desorption technique was preferred for analysis of polymer additives because of undesirable fragmentation from FAB experiments [93]. 

Attack on Halogen. Predictably, the 3-bromo-3-cyano-imides (56) and (57) form quasiphosphonium salts (58) with aryl phosphites, phosphonites, and phosphinites.47 In the case of (56) these salts cyclize to the oxazaphosphorane (59), which is in equilibrium with the iminophosphorane (60), depending on the phosphorus ester used. 

The use of copper catalysts based on chiral phosphorus ligands to assist 1,4-additions of dialkylzinc reagents has in recent years produced major breakthroughs, with excellent enantioselectivities. A number of monodentate and bidentate phos-phoramidites, phosphites, phosphonites, and phosphines are now available as chiral ligands for alkyl transfer to a variety of cyclic and acyclic enones. So far. 

For examples of asymmetric catalyses with BlNOL-derived monodentate phosphites, phosphonites, and phosphoramidites, see a) M. T. Reetz, G. Mehler, Angew. Chem. 2000, 112, 4047 Angew. Chem. Int. Ed. 2000, 39, 3889 ... 

The chemistry of phosphite, phosphonite and phosphinite complexes of palladium(II) generally resembles that of their phosphine analogues. Its description here will therefore be brief, attention being paid to those areas where differences in behaviour are apparent. 

Four similar papers reporting new cationic and neutral complexes of Pt group metals with phosphite, phosphonite and phosphinite ligands have appeared (see... 

Table 41 Preparations Phosphite, Phosphonite and Phosphinite Complexes...

This chapter covers the main synthetically useful phosphonylation reactions, the corresponding processes of phosphinylation and tertiary phosphine oxide formation along with some related reactions. In all these reactions the phosphorus reactant (a phosphite, phosphonite, phosphinite, or derivative or tautomer thereof) is the nucleophilic component, herein these reactants are referred to collectively as phosphorus(III) reactants/acids, as appropriate in general these reagents are best used freshly distilled. Syntheses of phosphonates, phosphinates and tertiary phosphine oxides by nucleophilic substitution at phosphorus is not covered (for reviews of this area see Refs 6 and 16). 

Rees and co-workers have carried out an extensive study of the addition of tri-methylsilyloxy phosphorus(lll) derivatives (phosphites, phosphonites, and phos-phinites, generated in situ) to aldimines to yield a-aminoalkyl-phosphonates, phosphinates and phosphine oxides (respectively, the transferred /V-TMS group being lost during work-up). Competition experiments demonstrated that the addition to imines is faster than that to the parent aldehydes. They found that the presence of electron-withdrawing groups in the imine slows the reaction. 

Mnltinnclear Re hydrides, in particnlar CO/phosphine complexes, with the hydride bridging two or three metals and componnds with H atoms bridging Re and other metals, for example, obtained from the reactions of Re polyhydrides with metal salts, have been reported. The coordination chemistry of hydrido/phosphine complexes has been extended, in a nnmber of cases, to related phosphite, phosphonite, or arsine complexes. ... 

Calculated AG( — 50°Q values are in the range 38-6 to 43-7 kJ mol and rate constants in the range 11 x 10 to 4-9 x 10 s . Similar studies on other Ni(ii) complexes are reported (54,242,243,252). Co(ii) complexes with ethyl phosphite, phosphonite, and phosphinite ligands (L) may be high spin complexes of the type C0CI2L2 or low spin, 5-coordinate complexes of the type C0CI2L3. In organic solvents the equilibrium ... 

Metal deactivator that acts as a hindered phenolic antioxidant. Used in conjunction with phenolic antioxidants, phosphites/ phosphonites, thio-synergists and other co-additives. Most suited for PA PE, Rubbers and PP applications. 

A common synthetic strategy involves reaction of an appropriate chlorophosphine and the amine (primary, secondary, aliphatic, aromatic) in the presence of base (usually triethylamine, pyridine, or DBU (l,8-diazabicyclo[5.4.0]undec-7-ene). Care is often required during these syntheses to exclude water, thereby preventing the formation of Ph2PP(0)Ph2. Work-up procedures are similar to those for the preparation of phosphites, phosphonites, etc. and yields are often high. In some cases this strategy may yield mixtures of (phosphino)amines in which both full and partial aminolysis has resulted. 

It has recently been demonstrated in our own laboratory that negatively substituted olefins of the type known as dienophiles react smoothly with phosphite, phosphonite, and phosphinite esters in the presence of a suitable proton donor (123,127). With the use of phenol for this purpose, reactions are exceptionally clean and high yields may be realized. Some representative examples are included in Table I. While ethanol or methanol are often satisfactory substitutes for phenol, the yields of phosphonate are generally lower and side reactions often occur, possibly due to the lessened efficiency of alcohol as a protonating agent. Yields of phosphonate for reactions in ethanol are indicated in brackets in Table I. Thus, in addition to the expected phosphonate from reaction of acrylamide and triethyl phosphite in ethanol, there were also ob-... 

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