Studien zur Synthese der Mitomycine, 2. Synthese des Mitosen‐Gerüstes durch intramolekulare Wittig‐Olefinierung

Flitsch, Wilhelm; Russkamp, P.; Langer, Werner

doi:10.1002/jlac.198519850712

Cited by 27 publications

(2 citation statements)

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“…While the Arbuzov rearrangement has long been known, apart from the thermally induced alkyl‐halide catalysis3 already mentioned and the related iodine4 or alkali‐metal–iodide5 catalysts, the only true thermal Arbuzov‐rearrangement catalyst described to date is nickel( II ) chloride 1d. 6 A few intramolecular rearrangements, limited to highly reactive phosphinites or requiring very high temperature or pressure, have been described,7 and no efficient room‐temperature catalysts have been described so far. Our idea was to test the use of oxophilic Lewis acids which could bind to the oxygen atom, and thus weaken the OC bond, enhancing the reaction rate of the second, energy‐requiring step of the Arbuzov rearrangement.…”

Section: Methodsmentioning

confidence: 99%

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

et al. 2003

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The Michaelis-Arbuzov rearrangement is one of the most extensively investigated reactions in organophosphorus chemistry, and is widely used in many fields of chemistry, from organic synthesis to catalyst design, to prepare phosphonates, phosphinates, and phosphane oxides.[1] This rearrangement involves the reaction of an ester of a trivalent phosphorus species R 1 R 2 PÀOR 3 with alkyl halides R 4 X. Although pentacoordinate phosphorane intermediates cannot be completely excluded, [1d] the generally accepted mechanism for this Michaelis-Arbuzov rearrangement (Scheme 1) involves formation of a phosphonium intermediate through nucleophilic addition of the phosphorus lone pair

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Section: Methodsmentioning

confidence: 99%

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

et al. 2003

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“…[7] Certain metal halides also serve as catalysts. A single clear-cut example of catalysis by nickel(II) chloride has been described by a German group; [8] most recently, oxophilic Lewis acids have been successfully employed. [9] Some organic compounds have also been used as catalysts.…”

Section: Introductionmentioning

confidence: 99%

Studies on the Efficient Generation of PhosphorusCarbon Bonds via a Rearrangement of P^III Esters Catalysed by Trimethylhalosilanes

Dąbkowski

Ozarek

Olejniczak

et al. 2009

Chemistry A European J

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Halotrimethylsilanes Me(3)SiX (X = Br, I) catalyse rearrangements of tricoordinate phosphorus esters R'R''P-OR into the corresponding phosphoryl systems R'R''P(O)R. This provides a simple and efficient route to a variety of structures containing phosphorus-carbon bonds, under mild conditions and with good yields. The reaction mechanism was investigated in detail by (31)P NMR spectroscopy and independent synthesis of the reaction intermediates. It has been demonstrated that the primary products of this catalytic reaction are halogeno P(III) structures R'R''PX and silyl ethers ROSiMe(3) and that they subsequently react to give the corresponding phosphorus silyl esters-Me(3)SiOPR'R''-and alkyl halides RX. At higher temperatures these intermediates then react to form R'R''P(O)R compounds. This paper also features the surprising observation that when esters Ph(2)POR and halotrimethylsilanes Me(3)SiX (X = Br, I) are used in 2:1 ratio, phosphonium salts Ph(2)R(2)P(+)X(-) and trimethylsilyl diphenylphosphinate--Ph(2)P(O)OSiMe(3)--are formed as the major products. Experimental evidence indicates that the mechanisms of both reactions are fundamentally different from that of the Michaelis-Arbuzov reaction. Me(3)SiCl is not reactive and this paper explains why.

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TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

Jones

Stanforth

1996

Organic Reactions

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In 1925 Fischer, Müller, and Vilsmeier published a paper describing the reaction between phosphoryl chloride and N ‐methylacetanilide, giving a number of products, including the quinolinium salt and another salt. The probable course of the reaction was given in a paper by Vilsmeier and Haack in 1927, and they made the important discovery that the reagent obtained from N ‐methylformanilide and phosphoryl chloride, represented as a salt, would react with N,N ‐dimethylaniline, giving 4‐ N,N ‐dimethylaminobenzaldehyde. No 2‐substituted products were observed in this reaction. Other N,N ‐dialkylaniline derivatives, including 3, N,N ‐trimethylaniline and 1‐ N,N ‐dimethylaminonaphthalene were also successfully used as substrates to prepare aromatic aldehyde derivatives. The gradual development of the reagent for synthesis was accompanied by interest in the nature of the reagent. It was discovered that other acid chlorides (e.g., thionyl chloride, carbonyl chloride, and oxalyl chloride) could be used in the reaction and that substituted amides other than formamides gave ketones, although in generally poorer yields. Thionyl chloride frequently gives sulfur‐containing products. The most commonly used amide is dimethylformamide (DMF) and there is now a consensus that the reagent formed from DMF and most acid chlorides, other than phosphoryl chloride, can be represented by the structure given in the chapter, and this is illustrated for the reaction between DMF and carbonyl chloride. The salt is a stable compound and is often isolated before being reacted with a substrate. It seems likely that the most commonly used reagent, that made from DMF and phosphoryl chloride, is an equilibrium mixture of iminium salts. Recent unpublished spectroscopic studies have indicated that in DMF solution there is an equilibrium mixture of iminium compounds. One of the electrophilic chloroiminium salts then reacts with a substrate in an electrophilic substitution process yielding an iminium salt, which is usually hydrolyzed to the aromatic aldehyde. Vinylogous chloroiminium salts can be prepared from the corresponding vinylogous formamide derivatives and these yield, after hydrolysis, α,β‐unsaturated products. This particular reaction is generally limited to more reactive substrates. The formation of carbon–carbon bonds to fully conjugated carbocycles and heterocycles is the subject of this chapter; a subsequent chapter considers carbon–carbon bond‐formation reactions in alkenes (including heterosubstituted alkenes such as enamines and enol ethers), alkynes, and activated methyl and methylene compounds (aldehydes, ketones, carboxylic acid derivatives, and nitriles). It is not surprising that the Vilsmeier reaction has been the subject of many review articles of varying scope and length. With so many excellent reviews dealing with the Vilsmeier reaction, its mechanism, and the structure of the various electrophilic reagents, coverage is restricted to important concepts rather than reiterate all the literature material. A brief description of the mechanism and regiochemistry of the Vilsmeier reaction is presented and this is elaborated with appropriate cases that deal with specific compound types.

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Studien zur Synthese der Mitomycine, 2. Synthese des Mitosen‐Gerüstes durch intramolekulare Wittig‐Olefinierung

Cited by 27 publications

References 13 publications

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

Studies on the Efficient Generation of PhosphorusCarbon Bonds via a Rearrangement of P^III Esters Catalysed by Trimethylhalosilanes

TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

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Studien zur Synthese der Mitomycine, 2. Synthese des Mitosen‐Gerüstes durch intramolekulare Wittig‐Olefinierung

Cited by 27 publications

References 13 publications

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

Lewis Acid Catalyzed Room‐Temperature Michaelis–Arbuzov Rearrangement

Studies on the Efficient Generation of PhosphorusCarbon Bonds via a Rearrangement of PIII Esters Catalysed by Trimethylhalosilanes

TheVilsmeier Reaction of Fully Conjugated Carbocycles and Heterocycles

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Studies on the Efficient Generation of PhosphorusCarbon Bonds via a Rearrangement of P^III Esters Catalysed by Trimethylhalosilanes