Catalytic Wittig and aza-Wittig reactions

Lao, Zhiqi; Toy, Patrick H.

doi:10.3762/bjoc.12.253

Cited by 96 publications

(66 citation statements)

References 47 publications

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“…825 This strategy has since been employed to promote Wittig, Appel, Staudinger, and Mitsunobu reactions, as well as other reactions thermodynamically driven through formation of a phosphine oxide. 44, 904–906 In 2010, O’Brien filed a patent involving the reducing strategy, “Catalytic Wittig Reaction and Mitsunobu reactions,” 907 implying the potential value of these catalytic reactions.…”

Section: Miscellaneous Topicsmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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The hallmark of nucleophilic phosphine catalysis is the initial nucleophilic addition of a phosphine to an electrophilic starting material, producing a reactive zwitterionic intermediate, generally under mild conditions. In this Review, we classify nucleophilic phosphine catalysis reactions in terms of their electrophilic components. In the majority of cases, these electrophiles possess carbon–carbon multiple bonds: alkenes (section 2), allenes (section 3), alkynes (section 4), and Morita–Baylis–Hillman (MBH) alcohol derivatives (MBHADs; section 5). Within each of these sections, the reactions are compiled based on the nature of the second starting material—nucleophiles, dinucleophiles, electrophiles, and electrophile–nucleophiles. Nucleophilic phosphine catalysis reactions that occur via the initial addition to starting materials that do not possess carbon–carbon multiple bonds are collated in section 6. Although not catalytic in the phosphine, the formation of ylides through the nucleophilic addition of phosphines to carbon–carbon multiple bond–containing compounds is intimately related to the catalysis and is discussed in section 7. Finally, section 8 compiles miscellaneous topics, including annulations of the Hüisgen zwitterion, phosphine-mediated reductions, iminophosphorane organocatalysis, and catalytic variants of classical phosphine oxide–generating reactions.

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Section: Miscellaneous Topicsmentioning

confidence: 99%

Phosphine Organocatalysis

et al. 2018

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“…Among the P-heterocycles with various ring size, the five-membered derivatives received special attention due to their optimal bond angles and shapes [13,14]. Besides their application as ligands [13,15], the five-membered heterocycles may also be valuable organocatalysts in reactions involving a P(III)-P(V) redox cycle, such as in catalytic Wittig-, aza-Wittig-, Staudinger-, Appel-and other reactions [16][17][18][19][20][21]. The ring strain of the four-and five-membered derivatives makes them highly susceptible to deoxygenation, thus they are ideal organocatalysts in P(III)-P(V) redox-coupled transformations [18,22,23].…”

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confidence: 99%

Preparation of 2-phospholene oxides by the isomerization of 3-phospholene oxides

Bagi¹,

Herbay²,

Péczka³

et al. 2020

Beilstein J. Org. Chem.

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A series of 1-substituted-3-methyl-2-phospholene oxides was prepared from the corresponding 3-phospholene oxides by double bond rearrangement. The 2-phospholene oxides could be obtained by heating the 3-phospholene oxides in methanesulfonic acid, or via the formation of cyclic chlorophosphonium salts. Whereas mixtures of the 2- and 3-phospholene oxides formed, when the isomerization of 3-phospholene oxides was attempted under thermal conditions, or in the presence of a base. The mechanisms of the various double bond migration pathways were elucidated by quantum chemical calculations.

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“…For the sake of simplicity we chose the most well‐established approach for the stereoselective synthesis of alkenes, based on Wittig or HWE reactions. The sustainability of these processes has been recently improved, by optimising catalytic variants of the Wittig reaction, to reduce the amount of the required phosphine, and solvent‐free protocols of the HWE olefination …”

Section: Resultsmentioning

confidence: 99%

Chemoselective Biohydrogenation of Alkenes in the Presence of Alkynes for the Homologation of 2‐Alkynals/3‐Alkyn‐2‐ones into 4‐Alkynals/Alkynols

et al. 2019

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The chemoselective hydrogenation of alkenes in the presence of alkynes is a very challenging transformation to achieve with traditional chemical methods. The development of an effective procedure to perform this transformation would enrich the tool-kit available to organic chemists for the development of useful synthetic routes, and the creation of novel structural motifs. The reduction of activated alkene bonds by ene-reductases (ERs) is completely chemoselective, because of the mechanism of the reaction. Thus, we investigated the use of ERs belonging to the Old Yellow Enzyme family for the reduction of α,β-unsaturated aldehydes with a conjugated C�C triple bond at the γ position. This reaction was exploited as the key step for the development of an effective homologation route to convert aryl and alkyl substituted propynals and butynones into 4-alkynals and 4-alkynols, avoiding some troublesome or hazardous steps of known synthetic routes. Scheme 4. Conversion of aldehydes (R)-8 a, b and alcohols (S)-10 a, b into derivatives of known absolute configuration.

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Catalytic Wittig and aza-Wittig reactions

Cited by 96 publications

References 47 publications

Phosphine Organocatalysis

Phosphine Organocatalysis

Preparation of 2-phospholene oxides by the isomerization of 3-phospholene oxides

Chemoselective Biohydrogenation of Alkenes in the Presence of Alkynes for the Homologation of 2‐Alkynals/3‐Alkyn‐2‐ones into 4‐Alkynals/Alkynols

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