Stepwise activation of “non-innocent” Cp* substituents – a Cp* based cascade reaction

Stubenhofer, Markus; Lassandro, Giuliano; Baláȥs, Gábor; Timoshkin, Alexey Y.; Scheer, Manfred

doi:10.1039/c2cc32690f

Cited by 14 publications

(6 citation statements)

References 48 publications

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“…After reaction with another 1 equiv of the phosphine, a stereoselective formation of triphosphines and 2-arsadiphosphines ( D ) coordinated by W(CO) 5 was observed, for which a diphosphene or arsaphosphene intermediate was proposed . If Cp*PH 2 is used as a primary phosphine, this reaction proceeds further via a new sequence of hydrophosphination, subsequent Cp* elimination, and retro-Diels–Alder reaction . In light of these initial results, the reactivity of the pentelidene complexes 1a , b with secondary and tertiary phosphines was of special interest.…”

Section: Introductionmentioning

confidence: 99%

“…In addition, the Cp* substituent can shift to an incoming substrate such as a nitrile to form P-containing heterocycles . Moreover, a Cp* radical elimination occurs under photolytic conditions and the remaining pentel radical [E{W(CO) 5 } 2 ] can be trapped by reactive compounds containing multiple bonds to yield, for example, stable triphospha or arsadiphospha radicals . However, the most important reactivity feature represents the electrophilicity of these starting materials, which leads to a nucleophilic attack of an incoming substrate at the pentelidene atom, as exemplified by reactions with primary phosphines.…”

Section: Introductionmentioning

confidence: 99%

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Versatile Reactivity of Bridged Pentelidene Complexes toward Secondary and Tertiary Phosphines

et al. 2013

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The reaction of the phosphinidene complex [Cp*P{W(CO) 5 } 2 ] (1a) with secondary and tertiary phosphines, respectively, proceeds via W(CO) 5 elimination to form the phosphoranylidene complexes [{W(CO) 5 }(Cp*)-P-P(H) i Pr 2 ] (2), [{W(CO) 5 }(Cp*)P-PMe i Pr 2 ] (7), and [{W(CO) 5 }(Cp*)P-PEt 3 ] (9). Other novel types of products, the phosphine-coordinated bridged parent phosphinidene complexes [{W(CO) 5 } 2 (H)P-PMe i Pr 2 ] (6a) and [{W-(CO) 5 } 2 (H)P-PEt 3 ] (8a), are obtained by elimination of 1,2,3,4-tetramethylfulvene. The latter reaction path is predominantly found for the arsinidene complex [Cp*As{W(CO) 5 } 2 ] (1b) to yield [{W(CO) 5 } 2 (H)As-PH i Pr 2 ] (4) upon reaction with HP i Pr 2 and, with tertiary phosphines, the products [{W(CO) 5 } 2 (H)As-PMe i Pr 2 ] (6b) and [{W(CO) 5 } 2 (H)As-PEt 3 ] (8b). If a secondary phosphine coordinates to a bridged parent pentelidene complex, Cp*H elimination occurs to form either HP[P i Pr 2 {W(CO) 5 }] 2 (3) or the phosphine-substituted diarsene complex W(CO) 5 [AsP i Pr 2 {W(CO) 5 }] 2 (5). Each of the new products has been characterized by X-ray structure analysis, NMR, and mass spectroscopy. In each case as a first step the Lewis acid/base adducts are formed, which was monitored by 31 P NMR spectroscopy. The different reaction pathways of the electrophilic pentelidene complexes [Cp*E{W(CO) 5 } 2 ] (E = P, As) have been emphasized by extended DFT calculations.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Versatile Reactivity of Bridged Pentelidene Complexes toward Secondary and Tertiary Phosphines

et al. 2013

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“…UV radiation induces elimination of a Cp* radical to yield stable triphospha- or arsadiphosphaallyl radicals in the reaction with diphosphenes . Only if MesCP reacts with [Cp*P{W(CO) 5 } 2 ] a ring expansion of the Cp* substituent has been found so far, and primary phosphines provoke hydrophosphination reactions to expand the Cp* moiety, yielding diphosphanorbornene derivatives …”

Section: Introductionmentioning

confidence: 99%

Transformation of a Phosphorus-Bound Cp* Moiety in the Coordination Sphere of Manganese Carbonyl Complexes

et al. 2013

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The reaction of Cp*PCl 2 with K[Mn(CO) 5 ] yields two novel anionic products, [Mn 2 (CO) 8 (μ-PC 11 H 14 O)] − (1 − ) and [Mn 2 (CO) 8 (μ-PHCp*)] − (2 − ), instead of the expected phosphinidene complexes with a delocalized Mn−P−Mn bond system. By treating these anionic complexes with [Ph 3 PAuCl], they are converted into corresponding neutral derivatives [Mn 2 (CO) 8 (μ-PC 11 H 14 O)(μ-AuPPh 3 )] (3) and [Mn 2 (CO) 8 (μ-PHCp*)(μ-AuPPh 3 )] (4). NMR investigations and X-ray structural analyses for 1 − , 3, and 4 show that the compounds 1 − and 3 as well as 2 − and 4 reveal similar molecular structures in which the neutral complexes 3 and 4 contain AuPPh 3 units bridging Mn−Mn bonds. In comparison to 1 and 3, complexes 2 and 4 possess one additional H atom bound at the P atom. The structures of 1 and 3 include a novel bicyclic unit consisting of a C 5 ring of the former Cp* moiety conjugated to a CCC(O)P four-membered ring. The latter is built by a CO group of a former Mn carbonyl fragment connecting a P and a C atom of the cycle. One of the methyl groups of the Cp* ligand became a CH 2 unit, resulting in two isomers containing an exocyclic CH 2 moiety in the positions three or five of the C 5 ring. Both isomers were found in the reaction mixture, with one as the major isomer. The proposed reaction pathway is based on XRD, NMR, and MS data and includes the reduction of a transient [Cp*P(Mn(CO) 5 ) 2 ] complex by [Mn(CO) 5 ] − , a proton transfer from the neutral to the reduced complex, and a successive reduction of the protonated species. The neutral bicyclic compound 3, containing a 2phosphacyclobutanone ring, is light sensitive and decomposes to tetramethylfulvene, possibly by a radical decarbonylation mechanism via a transient phosphacyclobutane derivative, [C 5 (CH 3 ) 4 (CH 2 )P(Mn(CO) 4 ) 2 AuPPh 3 ] (5), detected by NMR spectroscopy.

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“…Since then, several other theoretical studies Chapter 1 Short Review on Phosphirane: Structure, Reactivity and Synthesis 4 have been carried out at different levels of theory and they are in remarkable agreement with the thermodynamical parameters presented above. [29][30][31][32][33] 1.3 Phosphiranes: Reactivity…”

Section: Figure 13 Molecular Orbitals For Parent Phosphirane 26mentioning

confidence: 99%

“…[24][25][26] Moreover, the transient two equivalents of primary phosphine Cp*PH 2 to produce triphosphine involves intramolecular hydrophosphination in the reaction pathway (Scheme 2.11). 30 In addition, it has been discovered that when a phosphine oxide is directly bonded to an unsaturated group, the P-H bond of phosphine oxide is activated and the hydrophosphination reaction with Nbenzylidenemethylamine can proceed uncatalysed at room temperature (Scheme 2.12). 31 Likewise, intramolecular hydrophosphination of compound 10 is anticipated to take place yielding the ring-closing product 8. and 13 were then computed by DFT at the B3PW91/6-31G(d)-Lanl2dz (W) level.…”

Section: Scheme 25 Thermolysis Of 7-allyl-7-phosphanorbornadiene Commentioning

confidence: 99%

New aspects of phosphirane chemistry

Feny¹

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This thesis provides a detailed account of author's exploration on new aspects of phosphirane chemistry. Chapter one briefly reviews the theoretical and experimental works on phosphiranes that have been published until the middle of 2014. Chapter two describes the investigation on the influence of additional strain on phosphiranes. The subjects of the investigation are norbornane-annulated 1-methylphosphirane complexes. The stereochemistry of these complexes has further strained the annulated phosphiranes, leading to a number of structural distortions and selective decomplexation by CO under pressure. Chapter two also recounts the serendipitous discovery of phosphorus dimers from the thermolysis of 7-allyl-7phosphanorbornadiene complex. Chapter three illustrates the study on the activation of 1chlorophosphirane by aluminium trichloride. The subject of the study is cyclohexane-annulated 1-chlorophosphirane complex. It undergoes AlCl 3-catalysed electrophilic aromatic substitution with thiophene and ferrocene to produce 1-(2-thienyl)-and 1-ferrocenylphosphirane complexes respectively. In the absence of electron-rich arenes, a P-C bond cleavage catalysed by AlCl 3 takes place yielding dichloro(cyclohexyl)phosphine complex. The transient ferrocenylphosphinidene complex can be generated from 1-ferrocenylphosphirane complex and trapped with diphenylacetylene, trans-stilbene and water. 1.4.4 Formation of Two P-C Bonds 1.5 Conclusion References Chapter 2. Highly Strained Annulated Phosphiranes 2.1 Introduction 2.2 Results and Discussion 2.3 Conclusion 2.4 Experimental References Chapter 3. Activation of 1-Chlorophosphirane Complex by Aluminium Trichloride 3.1 Introduction 3.2 Results and Discussion 3.3 Conclusion 3.4 Experimental References Appendix vi LIST OF SCHEMES Scheme 1.1 Ring opening of aziridine-2-t-butyl carboxylate by primary amine Scheme 1.2 Copper-catalyzed ring expansion of vinyl oxirane Scheme 1.3 Ring cleavage by HCl or MeOH at room temperature Scheme 1.4 Hydrolysis of phosphirane with lone-pair-bearing substituent on ring carbon Scheme 1.5 Reaction of phospha[3]radialenes with dichlorophosphines Scheme 1.6 Ring-opening of phosphirane oxide by lithium amide Scheme 1.7 Ring opening of phosphirane tungsten complex by lithium amide Scheme 1.8 Synthesis of 1-phosphapentadienyl complex from 2-vinylphosphirane complex Scheme 1.9 Ring-opening of phosphirane complex via nucleophilic attack at phosphorus Scheme 1.10 Mechanism of ring opening of phosphiranes Scheme 1.11 Reaction of vinylphosphirane with methylenetrimethylphosphorane Scheme 1.12 Phosphirane-vinylphosphine rearrangement Scheme 1.13 Rearrangement of 2-chlorophosphirane into vinylchlorophosphine Scheme 1.14 Synthesis of triafulvene with phosphaspiropentene as intermediate Scheme 1.15 Ring opening of phosphiranium salt Scheme 1.16 Cationic ring-opening polymerisation of phosphirane vii Scheme 1.17 Thermal cleavage of phosphirane oxide Scheme 1.18 Thermal splitting of phosphirane yielding chloro(methylene)phosphine Scheme 1.19 Photolysis of 1-mesitylphos...

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Stepwise activation of “non-innocent” Cp* substituents – a Cp* based cascade reaction

Cited by 14 publications

References 48 publications

Versatile Reactivity of Bridged Pentelidene Complexes toward Secondary and Tertiary Phosphines

Versatile Reactivity of Bridged Pentelidene Complexes toward Secondary and Tertiary Phosphines

Transformation of a Phosphorus-Bound Cp* Moiety in the Coordination Sphere of Manganese Carbonyl Complexes

New aspects of phosphirane chemistry

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