- Ring size effects in cyclic fluorophosphites: Ligands that span the bonding space between phosphites and PF3
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The 5- to 8-membered cyclic fluorophosphites L5-8 have been prepared from the corresponding chlorophosphites which are derived from dihydroxyarenes or bis(trimethylsiloxy)arenes. Ligand L5 is very sensitive to hydrolysis but L6-8 are much more kinetically robust. The coordination chemistry of L5-8 has been explored with Mo(0), Pt(0) and Rh(i) and it is shown that the π-acceptor properties of L5-8 increase with decreasing ring size. The IR spectra and X-ray crystal structures of the [Mo(CO)4L2] complexes show that L5-8 lie between PF3 and P(OAr)3 in terms of their σ/π-bonding properties. The [PtL4] complexes are readily prepared from [Pt(nbe)3] and 4 equiv. of L5-8 whereas equilibrium mixtures of PtLx(nbe)y species form when 2 equiv. of L5-8 are added to [Pt(nbe)3]. The CO substitution reactions of [Rh2Cl2(CO)4] with L5-8 to give [Rh2Cl2L4] are evidence of the PF3-like ligand properties of L5-8. The trends in the properties of L5-8 are analysed in terms of their proximity to PF3 or P(OPh)3.
- Miles-Hobbs, Alexandra M.,Hunt, Eliza,Pringle, Paul. G.,Sparkes, Hazel A.
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- Thermoregulated phase-transfer ligands and catalysis. Part VI. Two-phase hydroformylation of styrene catalyzed by the thermoregulated phase-transfer catalyst OPGPP/Rh
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A novel nonionic water-soluble octylpolyglycol-phenylene-phosphite (OPGPP) was synthesized and the two-phase hydroformylation of styrene catalyzed by an OPGPP/Rh catalyst was investigated fully. The catalyst displayed excellent catalytic activity; high styrene conversion and high aldehyde yield (99.6 and 99.3%, respectively) were obtained at 80°C and 5.0 MPa, and the molar ratio of branched/normal aldehyde was 4.8. The experimental results revealed that there was a 'thermoregulated phase-transfer catalysis (TRPTC)' process present in the reactions.
- Chen, Ruifang,Liu, Xiaozhong,Jin, Zilin
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- Structure-property-reactivity studies on dithiaphospholes
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The reaction of either toluene-3,4-dithiol or benzene dithiol with phosphorus(iii) trihalides generates the corresponding benzo-fused 1,3,2-dithiaphospholes, RC6H3S2PX (R = Me (1), R = H (2); X = Cl, Br, I). The P-chloro-dithiaphospholes undergo: (a) halogen abstraction reactions with Lewis acids forming phosphenium cations; (b) substitution with LiHMDS base and; (c) reduction chemistry with sodium metal to generate the P-P σ-bonded dimer, (RC6H3S2P)2. Reduction catalysis of aldehydes with pinacolborane using dithiaphospholes is compared with their dioxaphosphole and diazaphosphole counterparts as pre-catalysts, revealing interesting differences in the reactivity of this series of compounds.
- Ould, Darren M. C.,Tran, Thao T. P.,Rawson, Jeremy M.,Melen, Rebecca L.
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p. 16922 - 16935
(2019/11/26)
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- Metathesis for catalyst design: Metacatalysis
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Prior studies have shown an effective way to produce diverse ligand sets for catalyst discovery is by using mixtures of monodentate forms to generate catalysts in situ. Research described here was performed to illustrate that alkene-functionalized monodentate ligands could be used in this way and in another that increases the diversity of the ligand library in an interesting way. Specifically, we hypothesized that as well as being used as monomers, these alkenes could be cross metathesized in situ immediately before the catalysis step. This combination of metathesis to form ligands in situ, then catalysis is referred to here as metacatalysis. In the event, a library of quinidine and quinine alkaloid-derived phosphites were tested as mixtures of monomers and dimers formed via metathesis in situ. The data obtained illustrated that metacatalysis can be used to identify ligands that positively and negatively modulate enantioselectivities in iridium-mediated hydrogenations of α,β-unsaturated carboxylic acid derivatives, relative to the mixtures of the monomeric forms used.
- Khumsubdee, Sakunchai,Burgess, Kevin
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p. 1326 - 1335
(2014/02/14)
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- Synthesis and structural characterization of a series of new chiral-at-metal ruthenium allenylidene complexes
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New chiral-at-metal ruthenium indenyl PPh3 phosphoramidite allenylidene complexes have been synthesized and structurally characterized. Through thermal ligand-exchange reactions with [RuCl(Ind)(PPh3) 2], the phosphoramidite ligands (R)-binol-N,N-dimethylphosphoramidite (5a), (R)-binol-N,N-dibenzylphosphoramidite (5b), (R,S)-binol-N-benzyl-N- α-methylbenzylphosphoramidite (5c), and (R)-catechol-2- methylpyrrolidinephosphoramidite [(R)-10] were converted into the complexes [RuCl(Ind)(PPh3)(L)] [L = 5a, 79%; 5b, 87%; 5c, 80%, (R)-10, 67%]. The complexes [RuCl(Ind)(PPh3)(5b)] and [RuCl(Ind)(PPh 3)(5c)] were obtained diastereomerically pure and, by reaction with propargylic alcohols, subsequently converted into the allenylidene complexes [Ru(Ind)(PPh3)(5b)(=C=C=CRR′)]+ PF6 - (R = R′ = Ph, 85%; R = Ph, R′ = Me, 66%; R = 2-furyl, R′ = Me, 94%; R = R′ = 4-fluorophenyl, 76%; R = 4-methoxyphenyl, R′ = Me, 66%) and [Ru(Ind)(PPh3)(5c)(=C=C=CRR′)] + PF6- (R = R′ = Ph, 91%; R = Ph, R′ = Me, 72%; R = 2-furyl, R′ = Me, 93%), which were also obtained diastereomerically pure. Complex [RuCl(Ind)(PPh3)(5b)] and three of the new allenylidene complexes were characterized structurally, which showed that the chiral information was transferred from the precursor complex to the corresponding allenylidenes. Dynamic NMR experiments showed that during the synthesis of allenylidene complexes only one diastereomer was formed. The research presented herein has an impact on the chemistry of chiral allenylidene complexes as catalysts and as potential intermediates in propargylic substitution reactions. Chiral-at-metal ruthenium chloro indenyl phosphoramidite complexes have been converted into the corresponding allenylidene complexes, some of which have been structurally characterized. The chiral information was transferred from the chloro precursor complexes to the allenylidene complexes, which were obtained as optically pure diastereomers. Only one diastereomer was formed during the syntheses. Copyright
- Costin, Stephen,Widaman, Andria K.,Rath, Nigam P.,Bauer, Eike B.
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scheme or table
p. 1269 - 1282
(2011/06/09)
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- IR, proton, and carbon-13 NMR spectral characterization of some chiral and achiral aminophosphines and their selenides
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Though aminophosphines have been known for a century, and a large variety of such compounds has been synthesized for different aspects of their chemistry, until now, no examples are available on phosphines containing three different amino substituents. In this study, the first examples of such chiral tris(amino)phosphines and o-phenylenedioxo(amino)phosphines were successfully synthesized using condensation reactions, and they were converted to their respective selenides using a simple oxidative addition reaction. The compounds are characterized by IR, 1H, and 13C NMR spectral techniques, and the spectral aspects are presented. The spectral studies (i) indicated that they are indeed powerful tools for structural elucidation of compounds; (ii) showed the effect of heavier selenium atom on the P-N bond rotation process; and (iii) further supported the fact that dipolar structure predominates over the -bond structure for the aminophosphine selenides. Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.
- Gopalakrishnan, Janarthanan,Rao, M. N. Sudheendra
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scheme or table
p. 754 - 764
(2010/07/05)
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- High yield synthesis of cyclic phosphites, phosphates, sulphites and sulphates of catechol and glycol mediated by hypervalent silicon centres
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Room temperature reactions of both tris(catecholato)silicate, M2[Si(o-C6H4O2)3] {M=Na, Et3NH} and glycolato silicate, K2[Si2(O2C2H4)5] with PCl3, POCl3, SOCl2 and SO2Cl2 proceed exothermally and afford easy isolation of the corresponding cyclic derivatives of catechol/glycol (1-8) in high yield, exemplifying the merit of hypervalent silicon centres in synthesis. (Et3NH)2[Si(o-C6H4O2)3] afford near quantitative conversions.
- Kingston,Sudheendra Rao
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p. 4841 - 4844
(2007/10/03)
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- FEATURES OF THE REACTION OF N-BENZOYL- AND N-PHOSPHINOYL-TRIFLUOROACETIMIDOYL CHLORIDES WITH PHOSPHORUS(III) AMIDES
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Reaction of N-substituted trifluoroacetimidoyl chlorides CF3C(Cl)=NX with P(III) amides leads to aminophosphonium salts CF3C+(NR2)3>=NX Cl-, which are stable in the solid state and decompose in solvents of low polarity to give amidines CF3C(NR2)=NX and aminochlorophosphines (R2N)nPCl(3-n).The stability of these salts decreases in the following series of X: PhC(O) > Cl2P(O) > (EtO)2P(O), and of R: Et > Me; and increases with increase in solvent polarity.Reaction of imidoyl chlorides with o-phenylene diethylphosphoramidite depends on the nature of the N-substituent: with X = PhC(O) -cycloaddition is realized, leading to spirophosphoranes, while with X = P(O)Cl2 or P(O)(OEt)2 amination occurs, leading to formation of amidines and aminochlorophosphines.In the reactions of imidoyl chlorides with Ph3P the phosphorane Ph3PF2 was detected, which was probably formed via halogenophilic attack.
- Onys'ko, P. P.,Kolodka, T. V.,Kolotilo, N. V.,Kudryavtsev, A. A.,Sinitsa, A. D.
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p. 359 - 364
(2007/10/02)
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- LIGAND EXCHANGE BETWEEN CYCLIC CHLORIDES CONTAINING TRI- AND PENTACOORDINATED PHOSPHORUS
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The halogenophilic reactions of soft bases and cyclic P(V) chlorides are followed by ligand exchange between the initial P(V) chloride and its reduced P(III) form resulting in spirocyclic compounds.
- Timokhin, B. V.,Dmitriev, V. K.,Kazantseva, M. V.
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p. 2063 - 2065
(2007/10/02)
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- REACTIONS OF 2,2,2-TRICHLORO-4,5-BENZO-1,3,2-DIOXAPHOSPHOLANE WITH DISILYLATED AMIDES OF ACETIC, PHOSPHORIC, AND SULFONIC ACID
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2,2,2-Trichloro-4,5-benzo-1,3,2-dioxaphospholane reacts with disilylated amides of acetic, phosphoric, and sulfuric acids with separation of trimethylchlorosilane and formation of N-substituted imidochlorophosphates.As a rule, the latter are instable and undergo β-decomposition and yield acid chlorides with three- and four-coordinated phosphorus atoms.
- Pudovik, M. A.,Kibardina, L. K.,Pudovik, A. N.
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p. 548 - 550
(2007/10/02)
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- LIGAND EXCHANGE BY HALOGENATION OF PIII COMPOUNDS
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The chlorination of several acyclic and cyclic PIII compounds at 0 deg C is discussed.Often a ligand exchange reaction is observed.
- Gloede, Joerg
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p. 155 - 158
(2007/10/02)
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- DERIVATE DES PHOSPHORSAEURE-o-PHENYLENESTERS. 27; REAKTIONEN DES DI-o-PHENYLENDIOXY-CHLOROPHOSPHORANS MIT ESTERN P-HALTIGER SAEUREN - SPALTUNG DES P-SPIROSYSTEMS
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The title compound 1 reacts with phosphites, phosphonate, phosphates and pentaoxyphosphorane to the o-phenylene phosphates 5, 7 and 9 resp. to the pentaoxyphosphoranes 2 and 13.A mechanism is proposed.
- Gloede. Joerg
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- Hindered phenyl phosphites
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Compounds of the formula STR1 WHEREIN R1 and R2 are independently alkyl or hydrogen, provided only one of R1 and R2 is hydrogen, R3 is --(A)q --COOR4 or CN, where A is alkylene, R4 is alkyl, phenyl or alkyl substituted phenyl, q is 0 or 1, m and n are each 1 or 2, the values of m and n being such that the trivalent state of P is satisfied, R is (a) halogen, (b) hydroxyl, provided that n is 1 when R is hydroxyl, (c) --XR5 wherein X is S or O, and R5 is alkyl, phenyl, alkyl substituted phenyl, or when X is O, R5 is alkanoyl, benzoyl, or alkyl substituted benzoyl, (d) a group of the formula STR2 wherein R6 is phenylene, alkyl substituted phenylene, or alkylene, X is as defined above, and m and n are each 1, (e) a group of the formula STR3 wherein R7 is hydrocarbyldiacyl, R1, R2 and R3 are as defined above, and m is 2 and n is 1, or (f) a group of the formula STR4 wherein R1, R2 and R3 are as defined above, and m and n are each 1, are suitable for stabilizing organic material against thermal, oxidative and ultraviolet light degradation.
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