David S Glueck

David S Glueck
Dartmouth College · Department of Chemistry

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124
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4,274
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July 1992 - present
Dartmouth College

Publications

Publications (124)
Article
Tetrahedral main group compounds are normally configurationally stable, but P-epimerization of the chiral phosphiranium cations syn - or anti -[Mes*P(Me)CH2CHPh][OTf] (Mes* = 2,4,6-(t-Bu)3C6H2) occurred under mild conditions at 60 °C in CD2Cl2 , resulting in isomerization to give a syn -enriched equilibrium mixture. Ion exchange with excess [NBu4 ]...
Article
Tetrahedral main group compounds are normally configurationally stable, but P‐epimerization of the chiral phosphiranium cations syn ‐ or anti ‐[Mes*P(Me)CH2CHPh][OTf] (Mes* = 2,4,6‐(t‐Bu)3C6H2) occurred under mild conditions at 60 °C in CD2Cl2 , resulting in isomerization to give a syn ‐enriched equilibrium mixture. Ion exchange with excess [NBu4 ]...
Article
Hydration of nitriles is catalyzed by the enzyme nitrile hydratase, with iron or cobalt active sites, and by a variety of synthetic metal complexes. This Perspective focuses on parallels between the reaction mechanism of the enzyme and a class of particularly active catalysts bearing secondary phosphine oxide (SPO) ligands. In both cases, the key c...
Article
P-Stereogenic secondary phosphine oxides [SPOs, RR′P(O)H], valuable ligands for metal complexes in asymmetric catalysis, are also building blocks for other chiral phosphorus derivatives. This short review summarizes methods used for asymmetric synthesis of P-stereogenic SPOs. 1 Introduction 2 Configurational Stability of P-Stereogenic SPOs 3 Classi...
Article
Metal-catalyzed asymmetric synthesis of P-stereogenic phosphines is a potentially useful approach to a class of chiral ligands with valuable applications in asymmetric catalysis. We introduced this idea with chiral platinum and palladium catalysts, exploiting rapid pyramidal inversion in diastereomeric metal–phosphido complexes (ML*(PRR′)) to contr...
Article
Kinetic separation of the commercially available cis/trans-(+)-limonene oxide mixture by ring opening with primary phosphido nucleophiles LiPHR (R = ferrocenyl, Ph, Cy, t-Bu, Mes* (Mes* = 2,4,6-(t-Bu)3C6H2)), followed by treatment with aqueous NH4Cl and H2O2, gave unreacted cis-(+)-limonene oxide and diastereoenriched mixtures of the secondary phos...
Article
Metal-catalyzed addition of P–H bonds to alkenes, alkynes, and other unsaturated substrates in hydrophosphination and related reactions is an atom-economical approach to valuable organophosphorus compounds. Understanding the mechanisms of these processes may enable synthetic improvements and development of new reactions. The first step in several c...
Article
Diastereoselective coordination of racemic secondary phosphines (PHRR') to Cu(I) precursors containing chiral bis(phosphines) (diphos*) was explored as a potential route to P-stereogenic phosphido complexes. Reaction of [Cu(NCMe)4][PF6] with chiral bis(phospholanes) gave [Cu(diphos*)2][PF6] (diphos* = ( R, R)-Me-DuPhos (1), ( R, R)-Et-DuPhos (2), o...
Article
Oxidative addition of methylene chloride to Pd((R,R)-Me-DuPhos)(L) (1–3; L = P(t-Bu)3, PCy3, or trans-stilbene) gave Pd((R,R)-Me-DuPhos)(CH2Cl)(Cl) (4). Treatment of [Rh(COD)(Cl)]2 with (R,R)-Me-DuPhos at low temperature in THF or CH2Cl2 afforded [Rh((R,R)-Me-DuPhos)(Cl)]2 (5). At room temperature, these reactions also gave the byproduct [Rh((R,R)-...
Article
A known ligand precursor, prepared by an improved method from 1,3-bis(bromomethylbenzene), a base, and (R,R)-2,5-dimethylphospholane-borane, was deprotected with DABCO and used to prepare chiral m-xylene-based PCP pincer complexes. Reaction with Ni(DME)Br2 and NEt3 gave square planar Ni(DuPinPhos)(Br) (9), which was crystallographically characteriz...
Article
Tandem alkylation/arylation of primary phosphines PH2R (R = Ph, Cy, Fc, FcCH2; Fc = ferrocenyl) with 5-bromo-6-chloromethylacenaphthene (1) and 2 equiv of NaOSiMe3 using the catalyst precursor Cu(IPr)(Cl) gave a series of 1-phosphapyracenes (R-PyraPhos, 2a–d), which were isolated as borane adducts 3a–d. Similar reactions of the chiral air-stable pr...
Article
Reaction of the enantiomerically enriched P-stereogenic phosphiranes syn-(RP,SC)-Mes*PCH2CH(Ph) (syn-1) and anti-(SP,SC)-Mes*PCH2CH(Ph) (anti-2, Mes* = 2,4,6-(t-Bu)3C6H2) with metal complex precursors gave Au(L)(Cl) (L = 1 (3); L = 2 (4)), trans-ML2Cl2 (L = 1, M = Pd (5), Pt (6)), Pd(η³-C3H5)(L)(Cl) (L = 1 (7)), and trans-RhL2(CO)(Cl) (L = 1 (8); L...
Article
Nucleophilic substitution results in inversion of configuration at the electrophilic carbon (SN2) or racemization (SN1). Stereochemistry at the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secon...
Article
Nucleophilic substitution results in inversion of configuration at the electrophilic carbon (SN2) or racemization (SN1). Stereochemistry at the nucleophile is rarely considered, but phosphines, which have a high barrier to pyramidal inversion, attack electrophiles with retention of configuration at P. Surprisingly, cyclization of bifunctional secon...
Article
For investigation of structure-property relationships in copper phosphine halide complexes, treatment of copper(I) halides with chiral bis(phosphines) gave dinuclear [Cu((R,R)-i-Pr-DuPhos)(μ-X)]2 [X = I (1), Br (2), Cl (3)], [Cu(μ-((R,R)-Me-FerroLANE)(μ-I)]2 (5), and [Cu((S,S)-Et-FerroTANE)(I)]2 (6), pentanuclear cluster Cu5I5((S,S)-Et-FerroTANE)3...
Article
To develop Rh-catalyzed dehydrocoupling for stereocontrolled synthesis of P–P bonds, we prepared potential intermediates, chiral rhodium phosphine-phosphido complexes, and investigated their stoichiometric and catalytic transformations. Treatment of [Rh(diphos*)(COD)][X] with the bis(secondary phosphine) IsHPCH2PHIs (1, Is = 2,4,6-(i-Pr)3C6H2) gave...
Article
The selectivity of catalytic asymmetric transformations of bifunctional symmetrical substrates often depends on the linker between the two reactive sites. If the catalyst controls the selectivity of reactions at both sites, the rac product will be formed in high enantiomeric ratio (er) via asymmetric amplification. Substrate control may augment thi...
Article
Alkylation of MeC(CH2PHPh)3 1 with 2-cyanobenzyl bromide and NaOSiMe3 using the catalyst precursor Pt((R,R)-Me-DuPhos)(Ph)(Cl) gave a mixture of tris(phosphines) enriched in C3-MeC(CH2PPh(CH2(o-C6H4CN))3 3; Cu-catalyzed phosphination yielded C1-enriched 3. Oxidation of 3 by sulfur or H2O2 formed MeC(CH2P(E)Ph(CH2(o-C6H4CN))3 (E = S 4; E = O 5). Rep...
Article
Metal-mediated synthesis of a new heterocycle, 1-phenyl-phosphapyracene (Ph-4, Ph-PyraPhos), by tandem phosphination/cyclization of peri-substituted 5-bromo-6-chloromethylacenaphthene (3) was investigated for comparison to Pt-catalyzed formation of 1-phosphaacenaphthenes (2, AcePhos) from the analogous naphthalene precursor (1). Reaction of PH2Ph w...
Article
Reaction of the bis(phosphine) rac-IsMePCH2PMeIs (Is = 2,4,6-(i-Pr)3C6H2) with two equiv of CuI gave the complex Cu4I4(rac-IsMePCH2PMeIs)2 (1) as a mixture of two diastereomers. The crystal structure of 1•4CHCl3 showed it adopted a distorted “octahedral” geometry with a rectangular Cu4 plane, two asymmetrically bridging µ4-iodides, two µ2-iodides a...
Article
The complexes Pt((R,R)-Me-DuPhos)(Ph)(Cl) (1) and Pt((R,R)-i-Pr-DuPhos)(Ph)(Cl) (2) have been used as catalyst precursors in Pt-catalyzed asymmetric alkylation of secondary phosphines. To investigate structure–reactivity–selectivity relationships in these reactions, analogous complexes with different bis(phospholane) ligands and/or Pt-hydrocarbyl g...
Article
Although the pyramidal inversion barriers in diphosphines (R(2)P-PR(2)) are similar to those in phosphines (PR(3)), P-stereogenic chiral diphosphines have rarely been exploited as building blocks in asymmetric synthesis. The synthesis, reactivity, and resolution of the benzodiphosphetane trans-1,2-(P(t-Bu))(2)C(6)H(4) are reported. Alkylation with...
Article
Treatment of M(dppe)Cl2 (M = Pd, Pt) or Pt((R,R)-Me-DuPhos)Cl2 with IsHPCH2PHIs (1; Is = isityl = 2,4,6-(i-Pr)3C6H2) and 2 equiv of NaOSiMe3 gave the mononuclear diphosphametallacyclobutane complexes M(dppe)(IsPCH2PIs) (M = Pd (2), Pt (3)), or Pt((R,R)-Me-DuPhos)(IsPCH2PIs) (4). Dynamic processes involving phosphorus inversion and rotation about th...
Article
Asymmetric deprotonation of PMe2(t-Bu)(BH3) with s-BuLi/(−)-sparteine, followed by treatment with MeSiCl3, gave a 2.6:1 mixture of the C3- and C1-symmetric triphosphine–boranes MeSi(CH2PMe(t-Bu)(BH3))3 (3). Recrystallization gave highly diastereomerically and enantiomerically enriched C3-3. After deprotection with morpholine, the triphosphine (R)-M...
Article
Catalytic asymmetric transformations of bifunctional symmetrical substrates pose interesting problems in selectivity. In one extreme, catalyst control leads to identical selectivity at both sites, and amplification of chirality in the product. This improved enantiopurity comes at the expense of reduced yield; the undesired meso byproduct must be se...
Article
The oxidative electrochemistry of P(CH2Fc)3 and three of its derivatives was examined. The electrochemistry of these compounds is sensitive to the functionality added to the phosphorus lone pair and the supporting electrolyte used.
Article
Phosphinoquinoxalines were prepared by treatment of 2,3-dichloroquinoxaline (3) with phosphorus nucleophiles. The Arbuzov reaction of 3 with PPh(O-i-Pr)2 gave a mixture of diastereomers of 2,3-(PPh(O)(O-i-Pr))2quinoxaline (6); the crystal structure of rac-6 was determined, but attempts at reduction to yield bis(phenylphosphino)quinoxaline 7 resulte...
Article
A Grignard reagent derived from (−)-menthyl chloride has been reported to be a 1:1 mixture of menthyl magnesium chloride and neomenthyl magnesium chloride, which do not interconvert. Addition of an excess of this reagent to Au(PPh3)(Cl) or Pt(dppe)Cl2 gave Au(PPh3)(Men) (1) and Pt(dppe)(Men)(Br) (2), respectively. Crystallographic studies of these...
Article
Cu(I) catalysts for alkylation of diphenylphosphine were developed. Treatment of [Cu(NCMe)(4)][PF(6)] (1) with chelating ligands gave [CuL(NCMe)][PF(6)] (2; L = MeC(CH(2)PPh(2))(3) (triphos), 3; L = 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene (XantPhos)). These complexes catalyzed the alkylation of PHPh(2) with PhCH(2)Br in the presence of the...
Chapter
AbstractThis chapter describes recent advances in metal-catalyzed C–P bond formation, which may be classified into two types of reactions. In hydrophosphination and related processes, P–H groups add across unsaturated C–X (X = C, N, O) bonds. Phosphination of electrophiles typically results in substitution at sp2 or sp3 carbon; the P–H group is rem...
Article
Catalytic asymmetric alkylation of the bis(secondary phosphines) IsHP(CH2)nPHIs (1a−e, n = 1−5, Is = isityl = 2,4,6-(i-Pr)3C6H2) with benzyl bromide using the base NaOSiMe3 and the catalyst precursor Pt((R,R)-Me-DuPhos)(Ph)(Cl) gave the bis(tertiary phosphines) Is(PhCH2)P(CH2)nP(CH2Ph)Is (2a−e, n = 1−5) via the intermediates Is(PhCH2)P(CH2)nPHIs (4...
Article
Treatment of 2 equiv of Au(THT)Cl (THT = tetrahydrothiophene) with the bis(secondary) phosphines HP(R) approximately PH(R) (linker approximately = (CH(2))(3), R = Mes = 2,4,6-Me(3)C(6)H(2) (1), R = Is = 2,4,6-(i-Pr)(3)C(6)H(2) (2), R = Ph (4); approximately = (CH(2))(2), R = Is (3); HP(R) approximately PH(R) = 1,1'-(eta(5)-C(5)H(4)PHPh)(2)Fe (5)),...
Article
Alkylation of the bis(secondary) phosphine IsHP(CH2)2PHIs (1; Is = isityl = 2,4,6-(i-Pr)3C6H2) with 2-(bromomethyl)naphthalene using 10 mol % of the catalyst precursor Pt((R,R)-Me-DuPhos)(Ph)(Cl) and the base NaOSiMe3 selectively yielded meso-IsP(CH2Ar)(CH2)2P(CH2Ar)(Is) (2; Ar = 2-naphthyl; dr = meso/rac ratio = 3.4:1). Half-alkylated IsP(CH2Ar)(C...
Article
Syntheses of the known ferrocenylmethylphosphines FcCH2PH2 (2, Fc=(η5-C5H4)Fe(η5-C5H5)), (FcCH2)2PH (3), and (FcCH2)3P (4) have been reinvestigated. The reaction of [FcCH2NMe3][I] with P(CH2OH)3, generated from [P(CH2OH)4][Cl] and KOH, gave a mixture of the major product (FcCH2)P(CH2OH)2 (1) and over-alkylated (FcCH2)2P(CH2OH) (9). Treatment of pur...
Article
Many important reactions that lead to carbon-heteroatom bond formation involve attack of anionic heteroatom nucleophiles, such as hydroxides, alkoxides, amides, thiolates and phosphides, at carbon. Related catalytic transformations are mediated by late transition metal complexes of these groups, which remain nucleophilic on metal coordination as a...
Article
This perspective describes the use of 31P NMR spectroscopy in an ongoing research project on enantioselective P−C bond formation catalyzed by platinum and palladium Duphos complexes. This technique was used to characterize catalyst precursors, intermediates and products, to determine equilibrium and rate constants, and to measure the enantiomeric e...
Article
Enantioselective tandem alkylation/arylation of primary phosphines with 1-bromo-8-chloromethylnaphthalene catalyzed by Pt(DuPhos) complexes gave P-stereogenic 1-phosphaacenaphthenes (AcePhos) in up to 74% ee. Diastereoselective formation of four P-C bonds in one pot with bis(primary) phosphines gave C2-symmetric diphosphines, including the o-phenyl...
Article
Platinum-catalyzed asymmetric alkylation of bis(secondary) phosphines was investigated. The modular design of the catalyst precursor Pt(diphos*)(R′)(Cl) and the substrates, a bis(secondary) phosphine HRPPHR and a benzyl halide, along with an efficient 31P NMR screening method, enabled rapid evaluation of the rate and diastereoselectivity of these r...
Article
Reduction of HAuCl4·3H2O with NaBH4 in THF/H2O in the presence of the primary phosphine PH2Mes* (Mes*=2,4,6-(t-Bu)3C6H2) gave a mixture of ca. 1.3nm diameter gold nanoparticles (1) and the known oligomers [Au(PHMes*)]n (2). Nanoclusters 1might contain phosphido (PHMes*) or phosphinidene (PMes*) surface ligands, or both; they were characterized by e...
Article
Chiral phosphanes, important ligands for metal-catalyzed asymmetric syntheses, are often prepared with compounds from the chiral pool, by using stoichiometric chiral auxiliaries, or by resolution. In some cases, this class of valuable compounds can be prepared more efficiently by catalytic asymmetric synthesis. This Concepts article presents an ove...
Article
This account summarizes our attempts to develop metal-catalyzed asymmetric syntheses of P-stereogenic phosphines. While such phosphines undergo pyramidal inversion slowly at room temperature, inversion is rapid in metal-phosphido com­plexes (M-PR2). These observations were the basis for catalytic, dynamic kinetic resolution processes in which racem...
Article
Asymmetric cross-coupling of aryl iodides (ArI) with secondary arylphosphines (PHMe(Ar'), Ar' = (2,4,6)-R3C6H2; R = i-Pr (Is), Me (Mes), Ph (Phes)) in the presence of the base NaOSiMe3 and a chiral Pd catalyst precursor, such as Pd((R,R)-Me-Duphos)(trans-stilbene), gave the tertiary phosphines PMe(Ar')(Ar) in enantioenriched form. Sterically demand...
Article
Enantioselective or diastereoselective intramolecular cyclization of functionalized secondary phosphines or their borane adducts catalyzed by chiral Pd(diphosphine) complexes gave P-stereogenic benzophospholanes in up to 70% ee. These results provide a new method for the synthesis of chiral phospholanes, which are valuable ligands in asymmetric cat...
Article
The catalyst precursor Pt((R,R)-Me-Duphos)(Ph)(Cl) (1) mediated asymmetric alkylation of the secondary phosphine PHMe(Is) (2; Is = 2,4,6-(i-Pr)3C6H2) with benzyl bromide in the presence of the base NaOSiMe3 to yield enantioenriched PMeIs(CH2Ph) (3). A mechanism for the catalysis has been proposed, on the basis of studies of the individual stoichiom...
Article
We recently proposed a new mechanism for platinum-catalyzed hydrophosphination of activated alkenes, in which nucleophilic attack of a phosphido ligand in the intermediate hydride complex Pt(diphos)(PR2)(H) (1) on the alkene H2CCH(X) (X = CN or CO2R) gave the zwitterion Pt(diphos)(H)(PR2CH2CHX) (2), containing a cationic Pt center and a phosphine l...
Article
Treatment of Pt halide precursors with the secondary phosphine PHMe(Is) in the presence of the base NaOSiMe3 gave the terminal phosphido complexes Pt(Duphos)(Ph)(PMeIs) (Is = 2,4,6-(i-Pr)3C6H2, Duphos = (R,R)-Me-Duphos (1), (R,R)-i-Pr-Duphos (2)), Pt((R,R)-Me-Duphos)(X)(PMeIs) (X = I (3), Cl (4)), and Pt((R,R)-Me-Duphos)(PMeIs)2 (5). Low-barrier py...
Article
Treatment of the terminal phosphido complexes Pt(dppe)(Me)(PPh(R)) (R = Ph (1), i-Bu (6)) with Pt(dppe)(Me)(OTf) gave the cationic μ-phosphido complexes [(Pt(dppe)(Me))2(μ-PPh(R))][OTf] (R = Ph (7), i-Bu (8)). Similarly, Pt((R,R)-Me-Duphos)(Me)(PPh(i-Bu)) (10) was converted to [(Pt((R,R)-Me-Duphos)(Me))2(μ-PPh(i-Bu))][OTf] (11). A fluxional process...
Article
The chiral Pt catalyst precursor Pt((R,R)-Me-Duphos)(Ph)(Cl) mediated alkylation of racemic secondary phosphines PHR(R') with benzyl halides in the presence of base to give enantioenriched tertiary phosphines PR(R')(CH2Ar). Similar reactions of bis(secondary) phosphines yielded chiral diphosphines in up to 93% ee and with good rac/meso diastereosel...
Article
Methylation of the crystallographically characterized primary alkylphosphine-borane PH2Men(BH3) (3, Men = (−)-menthyl) under phase-transfer conditions, followed by deprotection, gave the secondary phosphine PH(Me)(Men) (2). Cross-coupling of 2 with PhI in the presence of NaOSiMe3 selectively gave SP-PPh(Me)(Men) (1, L) with a variety of Pd catalyst...
Article
Pt-catalyzed addition of diethylphosphine to the diene cis,cis-mucononitrile gave the new diphosphine Et2PCH(CN)CH(CH2CH2CN)PEt2 as a 3:2 mixture of diastereomers. Two monophosphine−alkene intermediates in the hydrophosphination were characterized by NMR spectroscopy.
Article
Platinum-catalyzed hydrophosphination of activated olefins yields byproducts derived from more than one alkene. Formation of byproducts is suppressed by adding tert-butyl alcohol, consistent with a mechanism in which Michael addition of a nucleophilic Pt-PR2 group to the alkene yields a zwitterionic intermediate, which can undergo further conjugate...
Article
The chiral diamine (S,S)-bis(2,5-dimethylpyrrolidinyl)ferrocene (6) was prepared from diaminoferrocene and (2R,5R)-2,5-hexanediol cyclic sulfate in the presence of a base. The short C−N bond, long Fe−C(N) bond, and planar nitrogen observed in the crystal structure of 6 are consistent with efficient N-to-Cp electron donation. The resulting electron-...
Article
The chiral Pd(0) trans-stilbene complexes Pd(diphos*)(trans-stilbene) (diphos* = (R,R)-Me-Duphos, (R,R)-Et-Duphos, (R,R)-i-Pr-Duphos, (R,R)-Me-BPE, (S,S)-Me-FerroLANE, (S,S)-Me-DuXantphos, (S,S)-Et-FerroTANE, (R,S)-CyPF-t-Bu, (R,S)-PPF-t-Bu, (R,S)-BoPhoz) and Ni((R,R)-Me-Duphos)(trans-stilbene) were prepared by NaBH(OMe)3 reduction of the correspon...
Article
Nitroxide-mediated polymerization of the alkyne-functional monomer 4-(phenylethynyl)styrene allows the preparation of homopolymers and block copolymers with narrow molecular weight distributions. At higher conversions, side reactions, including addition of mediating nitroxides to alkyne groups, lead to broader molecular weight distributions. While...
Article
Nitroxide-mediated polymerization of the alkyne-functional monomer 4-(phenylethynyl)styrene allows the preparation of homopolymers and block copolymers with narrow molecular weight distributions. At higher conversions, side reactions, including addition of mediating nitroxides to alkyne groups, lead to broader molecular weight distributions. While...
Article
Gold-phosphido-monolayer-protected clusters (MPCs) of 1-2-nm diameter, Au(x)(PR2)y, analogues of the well-known thiolate materials Au(x)(SR)y, were prepared by NaBH4 reduction of a mixture of HAuCl4.3H2O and a secondary phosphine PHR2 in tetrahydrofuran/water. In comparison to the Au-thiolate MPCs, fewer of the larger phosphido groups are required...
Article
Treatment of a diblock copolymer containing an alkyne-functional block (polystyrene-block-poly(4-(phenylethynyl)styrene)) with dicobalt octacarbonyl (Co2(CO)8) leads to selective incorporation of Co2(CO)6 groups in the alkyne block. Examination of these composites in bulk and thin films by transmission electron microscopy reveals the formation of o...
Article
Pd[(S,S)-Et-FerroTANE](Ph)(I) undergoes diastereoselective phosphetane ring opening with concomitant Pd-to-P phenyl migration on mild heating. Cleavage of the resulting palladacycle with acid yields Pd[FerroCHAIN]I2, whose reaction with PhMgBr leads to facile opening of the second phosphetane ring and isolation of a complex of a novel C2-symmetric...
Article
Deprotonation of the phosphine complexes Au(PHR(2))Cl with aqueous ammonia gave the gold(I) phosphido complexes [Au(PR(2))](n)() (PR(2) = PMes(2) (1), PCy(2) (2), P(t-Bu)(2) (3), PIs(2) (4), PPhMes (5), PHMes (6); Mes = 2,4,6-Me(3)C(6)H(2), Is = 2,4,6-(i-Pr)(3)C(6)H(2), Mes = 2,4,6-(t-Bu)(3)C(6)H(2), Cy = cyclo-C(6)H(11)). (31)P NMR spectroscopy sh...
Article
The complexes Pd(diphos)(o-An)(I) (o-An = o-MeOC6H4; diphos = dppe (3), (S,S)-Chiraphos (4), (R,R)-Me-Duphos (5), (R,S)-t-Bu-Josiphos (6), (R)-Tol-Binap (7)) were prepared. Complex 6 catalyzed the coupling of PH(Me)(Ph)(BH3) (2) with o-AnI in the presence of base to yield PAMP−BH3 (P(Me)(Ph)(o-An)(BH3) (1)) in low enantiomeric excess. The course of...
Article
Wenngleich seit 25 Jahren bekannt blieben die Festkörperstrukturen und Eigenschaften in Lösung von Gold(I)-Phosphanyl-Komplexen wie [{Au(PR2)}n] bislang weitgehend unerforscht. Mögliche Strukturen wie die der gezeigten cyclischen Oligomere und linearen Polymere werden vorgeschlagen (L=Endgruppe).
Article
Treatment of Pd((S,S)-Chiraphos)(o-An)(I) (3, o-An = o-MeOC6H4) with either enantiomer of highly enantioenriched PH(Me)(Ph)(BH3) (1) gave the phosphido-borane complex Pd((S,S)-Chiraphos)(o-An)(P(Me)(Ph)(BH3)) (4) with retention of configuration at phosphorus, as shown by X-ray crystal structure determinations for both diastereomers of 4. Heating ei...
Article
The racemic secondary phosphine PH(Me)(Is) (1, Is = 2,4,6-(i-Pr)3C6H2) was coupled with PhI in the presence of NaOSiMe3 and the catalyst Pd((R,R)-Me-Duphos)(Ph)(I) (3) to give P(Ph)(Me)(Is) (2) in up to 78% ee. The intermediate phosphido complex Pd((R,R)-Me-Duphos)(Ph)(P(Me)(Is)) (5a,b) was observed as a mixture of diastereomers by low-temperature...
Article
Treatment of Pd(tmeda)Me2 with dimesitylphosphine (PMes2H, L) gave cis-PdL2Me2 (1). trans-ML2Cl2 (M=Pd (2), Pt (3)) were prepared from a variety of starting materials. The reaction of Pt(cod)Cl2 with L gave cis-PtL2Cl2 (4), which reacted with PPh3 to yield cis-Pt(L)(PPh3)Cl2 (5). cis-PtL2(Me)(Cl) (6) was prepared from L and Pt(cod)(Me)(Cl), while r...
Article
The cyclometalated cationic Pd(II) and Pt(II) complexes [M(diphos)(CH2C6H2Me2P(Mes)(H))][X] (5−8:  M = Pd, Pt; diphos = dppe (Ph2PCH2CH2PPh2), dppen (cis-Ph2PCHCHPPh2); Mes = 2,4,6-Me3C6H2; X = OTf, BF4) were prepared by thermolysis of the cations [M(diphos)(Me)(PMes2H)][X]. Deprotonation of 5−8 gave the neutral phosphido complexes M(diphos)(CH2C6H...
Chapter
IntroductionMetal-Catalyzed P(III)–H Additions: Hydrophosphination Metal-Catalyzed P(III)–H Additions to FormaldehydeMetal-Catalyzed P(III)–H Additions to AcrylonitrileMetal-Catalyzed P(III)–H Additions to Acrylate EstersPlatinum-Catalyzed Asymmetric HydrophosphinationOrganolanthanide-Catalyzed Hydrophosphination/CyclizationSummaryMetal-Catalyzed P...
Article
Coordinatively unsaturated pentamethylcyclopentadienyl pinacolate complexes of the group 9 transition metals (4−6) have been prepared and characterized. Photolysis of either the cobalt complex 4 or the rhodium complex 5 results in cleavage of the central carbon−carbon bond in the diolate, generating acetone. Various trapping studies demonstrate tha...
Article
The reaction of Pd(dppf)(Ph)(I) (1, dppf = Ph2PC5H4FeC5H4PPh2) with 1.5 equiv of PPh2H leads to the formation of the Pd(II) dinuclear complex Pd2I2(μ-dppf)(μ-H)(μ-PPh2) (2) and the phosphines PPh3 and dppf. The reaction of 1 with 1 equiv of PCy2H (Cy = cyclo-C6H11) slowly gives Pd2I2(μ-dppf)(μ-H)(μ-PCy2) (3). Complex 2 reacts further with PPh2H to...
Article
The cationic complexes [M(dppe)(R)(PHMes2)][OTf] (M = Pd, R = Me (1), Ph (2); M = Pt, R = Me (3), Et (4); dppe = Ph2PCH2CH2PPh2, Mes = 2,4,6-Me3C6H2, OTf = OSO2CF3) were prepared by the reaction of the corresponding M(dppe)(R)(X) (X = Cl, I) with AgOTf and PHMes2. When they were allowed to stand in THF or CH2Cl2 solution, the Pd complexes underwent...
Article
Platinum-catalyzed asymmetric hydrophosphination of activated olefins using the catalyst precursor Pt(R,R-Me-Duphos)(trans-stilbene) (1) gives chiral phosphines with control of stereochemistry at phosphorus or carbon centers. Stoichiometric reactions of 1 allow observation of P−H oxidative addition, diastereoselective olefin insertion, and reductiv...
Article
The acrylonitrile complexes Pt(diphos)(CH2CHCN) (diphos = dppe (1), dcpe (2); dppe = Ph2PCH2CH2PPh2, dcpe = Cy2PCH2CH2PCy2, Cy = cyclo-C6H11) are catalyst precursors and, for some substrates, resting states, during addition of P−H bonds in primary and secondary phosphines across the CC double bond of acrylonitrile (hydrophosphination). Oxidative ad...
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The chiral Pt(II) phosphido complex Pt(dppe)(Me)[P(Mes)(Men)] (dppe = Ph2PCH2CH2PPh2, Mes = 2,4,6-Me3C6H2, Men = (−)menthyl, 1) was prepared by proton transfer from racemic mesityl(−)menthylphosphine to the methoxide ligand of Pt(dppe)(Me)(OMe). Treatment of Pt(dcpe)[CH(Me)(CN)](Br) with alkali metal phosphides gives Pt(dcpe)[CH(Me)(CN)](PRR‘) (dcp...
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The Pt(II) phosphido methyl complexes Pt(dppe)(Me)(PPhR) (dppe = Ph2PCH2CH2PPh2, R = i-Bu, 1; R = Is = 2,4,6-(i-Pr)3C6H2, 2) have been prepared by proton transfer from secondary phosphines to the methoxide ligand of Pt(dppe)(Me)(OMe). Oxidative addition of ClC(O)C3F7 to Pt(PPh2Me)4 gives trans-Pt(PPh2Me)2(COC3F7)(Cl) (3); treatment of 3 with dppe y...