Phosphines catalyzed nucleophilic addition of azoles to allenes: synthesis of allylazoles and indolizines

Virieux, David; Guillouzic, Anne‐Francoise; Cristau, Henri‐Jean

doi:10.1016/j.tet.2006.01.055

Cited by 72 publications

(26 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Fu and co-workers [369] have optimized the carbene-catalyzed mode of β-alkylation of enolates, as shown in Scheme 58. Ph3P has been used as nucleophilic catalyst for the Umpolung addition of azoles to electron-deficient allenes [370]. Oxygen nucleophiles (alcohols [366], carboxylates [367]) and acidic nitrogen nucleophiles such as p-toluenesulfonamides have also been utilized as Umpolung catalysts in the nucleophilic γ-additions of conjugated yne-ketones and yne-esters [368].…”

Section: Umpolung Of Michael Acceptorsmentioning

confidence: 99%

See 1 more Smart Citation

Organocatalysis: Fundamentals and Comparisons to Metal and Enzyme Catalysis

et al. 2016

View full text Add to dashboard Cite

Catalysis fulfills the promise that high-yielding chemical transformations will require little energy and produce no toxic waste. This message is carried by the study of the evolution of molecular catalysis of some of the most important reactions in organic chemistry. After reviewing the conceptual underpinnings of catalysis, we discuss the applications of different catalysts according to the mechanism of the reactions that they catalyze, including acyl group transfers, nucleophilic additions and substitutions, and C-C bond forming reactions that employ umpolung by nucleophilic additions to C=O and C=C double bonds. We highlight the utility of a broad range of organocatalysts other than compounds based on proline, the cinchona alkaloids and binaphthyls, which have been abundantly reviewed elsewhere. The focus is on organocatalysts, although a few examples employing metal complexes and enzymes are also included due to their significance. Classical Brønsted acids have evolved into electrophilic hands, the fingers of which are hydrogen donors (like enzymes) or other electrophilic moieties. Classical Lewis base catalysts have evolved into tridimensional, chiral nucleophiles that are N-(e.g., tertiary amines), P-(e.g., tertiary phosphines) and C-nucleophiles (e.g., N-heterocyclic carbenes). Many efficient organocatalysts bear electrophilic and nucleophilic moieties that interact simultaneously or not with both the electrophilic and nucleophilic reactants. A detailed understanding of the reaction mechanisms permits the design of better catalysts. Their construction represents a molecular science in itself, suggesting that sooner or later chemists will not only imitate Nature but be able to catalyze a much wider range of reactions with high chemo-, regio-, stereo-and enantioselectivity. Man-made organocatalysts are much smaller, cheaper and more stable than enzymes.

show abstract

Section: Umpolung Of Michael Acceptorsmentioning

confidence: 99%

Section: Umpolung Of Michael Acceptorsmentioning

confidence: 99%

Organocatalysis: Fundamentals and Comparisons to Metal and Enzyme Catalysis

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In this context, triphenylphosphine has been used as nucleophilic catalyst for umpolung addition of azoles to electron-deficient allenes. This strategy offers a simple and efficient method for functional allylation of azoles under neutral conditions and affords heterocyclic substituted Michael olefins [142]. The catalytic cycle might be initiated by a nucleophilic addition of triphenylphosphine to the electron-deficient allene 88.…”

Section: Electrophilic Attack At N3mentioning

confidence: 99%

Five‐Membered Heterocycles: 1,3‐Azoles

Revuelta¹,

Machetti²,

Cicchi³

2011

Modern Heterocyclic Chemistry

View full text Add to dashboard Cite

“…2). Until recently, however, there were only isolated examples of intermolecular reactions of this type [≤30% yield (9)(10)(11); instead, another phosphine-catalyzed process, isomerization to the dienone (Eq. 2) (12, 13), often intervened], and there were no reports of an enantioselective variant.…”

mentioning

confidence: 99%

Phosphine-catalyzed asymmetric additions of malonate esters to γ-substituted allenoates and allenamides

Sinisi

Sun

2010

Proc. Natl. Acad. Sci. U.S.A.

101

View full text Add to dashboard Cite

Because carbonyl groups are ubiquitous in organic chemistry, the ability to synthesize functionalized carbonyl compounds, particularly enantioselectively, is an important objective. We have developed a straightforward and versatile method for catalytic asymmetric carbon-carbon bond formation at the γ-position of carbonyl compounds, specifically, phosphine-catalyzed additions of malonate esters to γ-substituted allenoates and allenamides. Mechanistic studies have provided insight into the reaction pathway.here are a variety of powerful methods for functionalizing carbonyl compounds in the α-and the β-positions, including classic approaches such as reacting enolates with electrophiles and adding nucleophiles to α,β-unsaturated carbonyl compounds (1, 2). In contrast, there are few general processes for incorporating new substituents in the γ-position of carbonyl compounds, particularly catalytic asymmetric reactions that form carboncarbon bonds (3).In pioneering early investigations, Trost and Lu demonstrated that phosphines can catalyze additions of certain carbon, nitrogen, and oxygen nucleophiles to the γ-position of 2-butynoates and 2,3-butadienoates (Eq. 1, EWG ¼ ester), as well as related compounds (4-8); for these electrophiles, the γ-carbon of the product is not a stereocenter. In contrast, for additions to homologues of these electrophiles, there is the potential to simultaneously form a new bond and to control the stereochemistry of the γ-carbon (Eq. 2). Until recently, however, there were only isolated examples of intermolecular reactions of this type [≤30% yield (9-11); instead, another phosphine-catalyzed process, isomerization to the dienone (Eq. 2) (12, 13), often intervened], and there were no reports of an enantioselective variant.

show abstract

Phosphines catalyzed nucleophilic addition of azoles to allenes: synthesis of allylazoles and indolizines

Cited by 72 publications

References 22 publications

Organocatalysis: Fundamentals and Comparisons to Metal and Enzyme Catalysis

Organocatalysis: Fundamentals and Comparisons to Metal and Enzyme Catalysis

Five‐Membered Heterocycles: 1,3‐Azoles

Phosphine-catalyzed asymmetric additions of malonate esters to γ-substituted allenoates and allenamides

Contact Info

Product

Resources

About