A«- phosphinic chloride

Larger chalcogen-phosphorus heterocycles, although less common in the literature, are accessible via a variety of synthetic routes.2,83,84 For example, the cyclic trimer (SPR)3 (R = 2,4,6-tri-tert-butylphenyl) contains a puckered six-membered P3S3 ring and is produced in the reaction of a phosphinic chloride with lithium sulfide (Equation 73).98 Additionally (R P)3Se5 (R = 2,4-di-tert-butyl-6-wopropoxyphenyl), synthesised from the oxidation of a primary phosphine with three equivalents of elemental selenium (Equation 74), has... 

The production of optically active phosphines and phosphine oxides may be achieved by scheme (13.68) starting with ( ) menthol and a phosphinous chloride. The components of the diastereoiso-meric mixture of phosphinates can be separated by fractional crystallisation and then processed as indicated in the scheme. Other methods of synthesis of optically active phosphinates have been devised [24]. 

The benzoic acid derivative 457 is formed by the carbonylation of iodoben-zene in aqueous DMF (1 1) without using a phosphine ligand at room temperature and 1 atm[311]. As optimum conditions for the technical synthesis of the anthranilic acid derivative 458, it has been found that A-acetyl protection, which has a chelating effect, is important[312]. Phase-transfer catalysis is combined with the Pd-catalyzed carbonylation of halides[3l3]. Carbonylation of 1,1-dibromoalkenes in the presence of a phase-transfer catalyst gives the gem-inal dicarboxylic acid 459. Use of a polar solvent is important[314]. Interestingly, addition of trimethylsilyl chloride (2 equiv.) increased yield of the lactone 460 remarkabiy[3l5]. Formate esters as a CO source and NaOR are used for the carbonylation of aryl iodides under a nitrogen atmosphere without using CO[316]. Chlorobenzene coordinated by Cr(CO)j is carbonylated with ethyl formate[3l7]. 

Butynediol is more difficult to polymerize than propargyl alcohol, but it cyclotrimerizes to hexamethylolbenzene [2715-91 -5] (benzenehexamethanol) with a nickel carbonyl—phosphine catalyst (64) with a rhodium chloride—arsine catalyst a yield of 70% is claimed (65). 

As already remarked, in compounds wer-IrX3 (PMe2Ph)3, the most labile ligand is the group X (X = H, Me, halogen) trans to a phosphine. The Ag+-assisted removal of chloride in (I) yields [IrCl2(H20)(PMe2Ph)3]+ (XII) where the H20 is very weakly bound (Ir—O 2.189 A, compare Ir(H20) + 2.041 A) and readily replaced. 

Chloroacylation of terminal aryl, alkyl or alkenyl alkynes [Le. the addition of RC(=0)-C1 across the CC triple bond] with aromatic acyl chlorides was catalysed by [IrCl(cod)(lPr)] (5 mol%) in good conversions (70-94%) in toluene (90°C, 20 h). Z-addition products were observed only, hitemal alkynes were umeactive. Surprisingly, a phosphine/[lr(p-Cl)(l,5-cod)]2 system under the same conditions provides decarbonylation products (Scheme 2.34) [117]. 

The reaction between 2-adamantyl halides and PCl /AlBr yields a mixture of di-2-adamantylphosphinic chloride and bromide together with (1-adamanyl)(2-adamantyl)phosphinic chloride 1-adamantyl halides are already known to afford only 1-adamantylphosphonic acid derivatives. 

Reactions of the hydroxy peptides with selected phosphine chlorides in the presence of a base and catalytic amounts of DMAP resulted the corresponding phosphinites, which readily form Pd and Pt complexes (Scheme 2). 

Use of tris(trimethylsilyl)phosphine as the phosphorus furnishing reagent in condensation reaction with a-diazocarboxylic chlorides (7) gave 2-trimethylsilyl-[l,2,3]diazaphospholes (9) in good yields (Scheme 3) [18],... 

Reaction of 3 with 1 equivalent of a phosphine results in formation of "phosphine-modified catalysts (4). The complex formed from 7r-allyl-nickel chloride, tricyclohexylphosphine, and methylaluminum dichloride (4a) has been isolated and its structure determined crystallographically (see Fig. 1) (57) The phosphine is bonded to the nickel atom, and interaction with the Lewis acid takes place via a chlorine bridge. The bridging chlorine atom is almost symmetrically bound to both the nickel... 

The main path of the palladium-catalyzed reaction of butadiene is the dimerization. However, the trimerization to form /j-1, 3,6,10-dodeca-tetraene takes place with certain palladium complexes in the absence of a phosphine ligand. Medema and van Helden observed, while studying the insertion reaction of butadiene to 7r-allylpalladium chloride and acetate (32, 37), that the reaction of butadiene in benzene solution at 50°C using 7r-allylpalladium acetate as a catalyst yielded w-1,3,6,10-dodecatetraene (27) with a selectivity of 79% at a conversion of 30% based on butadiene in 22 hours. 

The olefin binding site is presumed to be cis to the carbene and trans to one of the chlorides. Subsequent dissociation of a phosphine paves the way for the formation of a 14-electron metallacycle G which upon cycloreversion generates a pro ductive intermediate [ 11 ]. The metallacycle formation is the rate determining step. The observed reactivity pattern of the pre-catalyst outlined above and the kinetic data presently available support this mechanistic picture. The fact that the catalytic activity of ruthenium carbene complexes 1 maybe significantly enhanced on addition of CuCl to the reaction mixture is also very well in line with this dissociative mechanism [11] Cu(I) is known to trap phosphines and its presence may therefore lead to a higher concentration of the catalytically active monophosphine metal fragments F and G in solution. 

According to the latter approach, reducing sugars 128 were reacted with triethylammonium dimethyl boranophosphate in the presence of bis(2-oxo-3-oxazolidinyl)phosphinic chloride as condensing reagent, 3-nitro- 1,2,4-triazole as nucleophilic catalyst and A,A-diisopropyl-A-ethyl-amine to provide boranophosphate triester derivatives 129 as anomeric... 

FIGURE 8.21 Proposed mechanism for the BOP-Cl-mediated reaction of a carboxylate anion with a methylamino group. Formation of a mixed anhydride is followed by aminolysis that is facilitated by anchimeric assistance provided by the oxygen atom of the ring carbonyl.101 (van der Auwera Anteunis, 1987). BOP-C1 = fcw(2-oxo-3-oxazolidino)phosphinic chloride. 

C van der Auwera, MJO Anteunis. N,N-bis(2-oxo-3-oxazolidinyl) phosphinic chloride (BOP-C1) a superb reagent for coupling at and with iminoacid residues. Int J Pept Prot Res 29, 574, 1987. 

A similar mechanism to the previous ones was proposed by Deng, Shi and coworkers for the bis(2-oxo-3-oxazolidinyl)phosphinic chloride (BOP-Cl, 269) catalytic Beckmann rearrangement (equation 82). Addition of the Lewis acid zinc chloride improved the catalyst performance and amides were synthesized in excellent yields (92-99%). 

The reaction between dry phosphine and hydrogen iodide, first described in 1817 by J. J.Houtonde la Billardiere produces phosphonium iodide. The simplest laboratory preparation of this compound is by the hydrolysis of an intimate mixture of diphosphorus tetraiodide and white phosphorus According to X-ray diffraction investigations, phosphonium iodide crystallises in a caesium chloride type lattice 3m,32s). 326) hydrogen atoms... 

Peroxyphosphonate can be prepared by a similar reaction in the presence of pyridine instead of the sodium salt of the hydroperoxide. Peroxyphosphonates 72 are generally synthesized by the condensation of the corresponding phosphinic chloride with the sodinm salt of terf-butyl hydroperoxidate in a neutral solvent in the presence of sodinm snlfate, or alternatively, by the reaction of terf-butyl hydroperoxide with phosphinic chloride in the presence of pyridine . 

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