Sequential one-pot and three-component reactions of an N-heterocyclic carbene to form 4-(1,2,4-triazol-5-ylidene)pyrrolidine-2,5-diones: a tandem umpolung/annulation sequence via deoxy-Breslow intermediates

Matsuoka, Shin‐ichi; Tochigi, Yusuke; Takagi, Koji; Suzuki, Masato

doi:10.1016/j.tet.2012.08.076

Cited by 33 publications

(18 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[7] In addition, increasing the electrophilicity of the second Michael acceptor,a si nk etone 10,d iverted the reaction, with the competing Rauhaut-Currier product 11 being formed (eq. 3).…”

Section: Angewandte Chemiementioning

confidence: 99%

Enantioselective N‐Heterocyclic Carbene Catalysis by the Umpolung of α,β‐Unsaturated Ketones

2016

View full text Add to dashboard Cite

N-Heterocyclic carbene-catalyzed formation of β-anionic intermediates from enones has been employed in the enantioselective synthesis of 2-aryl propionates. The reaction was achievable using a homochiral 4-MeOC6H4 morpholinone catalyst allowing the first example of enantioselective catalysis by umpolung of α,β-unsaturated ketones. The reaction is high yielding, and shows robustness with reasonable generality. A mechanism is proposed in which the enantiodetermining protonation is achieved using either hexafluoroisopropanol or the formed naphthol product.

show abstract

Section: Angewandte Chemiementioning

confidence: 99%

Enantioselective N‐Heterocyclic Carbene Catalysis by the Umpolung of α,β‐Unsaturated Ketones

2016

View full text Add to dashboard Cite

show abstract

“…A number of NHCs have been implemented in the synthesis of triazaspirocycles, exhibiting reactivity with both aryl and vinyl isocyanates (Scheme 5 ) [47, 48]. Formation of NHCs can proceed via the corresponding metal-carbene complex [49], from the elimination of a haloform (CHX 3 ) [50], or from deprotonation of an imidazolium species [51, 52].…”

Section: Synthesis Of Triazaspirocyclesmentioning

confidence: 99%

Triazaspirocycles: Occurrence, Synthesis, and Applications

Gober

Carroll

Joullié

2016

MROC

View full text Add to dashboard Cite

Natural products bearing a triazaspirocyclic motif have received significant attention in recent years. These compounds, which feature three nitrogen atoms attached to one quaternary carbon forming a spirocyclic scaffold, exhibit a wide range of biological activity and have promising applications in materials as well as in drug discovery. In this review article, we will discuss triazaspirocycles in Nature, their biological activity, and applications. Methods for the synthesis of triazaspirocycles as well as the reactivity of triazaspirocyclic scaffolds will be reviewed.

show abstract

“…66. Some additional compounds have been published meanwhile, such as the adduct of 1,2,4-triazol-5-ylidene with phenylisocyanate, 67 several fluoroalkyl-substituted imidazolium-2-carbodithioates 68 and 2-thiocarboxylates. 69 Benzimidazole / isothiocyanate adducts 70 and chemosensors based on the adduct formation of CO 2 to benzobisimidazolium carbenes 71 have also been described.…”

Section: Scheme 26mentioning

confidence: 99%

Recent advances in neutral and anionic N-heterocyclic carbene – betaine interconversions. Synthesis, characterization, and applications

Schmidt¹,

Wiechmann²,

Freese³

2013

Arkivoc

View full text Add to dashboard Cite

Some mesoionic compounds, i.e. five-membered representatives of the class of conjugated mesomeric betaines (CMB), are in equilibrium with their tautomeric normal N-heterocyclic carbenes (nNHC). In addition, anionic N-heterocyclic carbenes, generated by deprotonation of mesoionic compounds, have been described. The first examples of conversions of crossconjugated mesomeric betaines (CCMB), 6-oxopyrimidinium-4-olates, into normal Nheterocyclic carbenes have been reported as well. CCMB such as imidazolium-4-carboxylate and pyrazolium-4-carboxylate can decarboxylate to form abnormal (aNHC) or remote N-heterocyclic carbenes (rNHC). Most conversions of betaines into N-heterocyclic carbenes start from pseudocross-conjugated mesomeric betaines (PCCMB) which can be regarded as heterocumulene adducts of nNHC. Thus, decarboxylations of imidazolium-2-carboxylates, 1,2,4-triazole-3-carboxylates, pyrazolium-3-carboxylates or indazolium-3-carboxylates yield N-heterocyclic carbenes which have been used in catalysis, complex chemistry, heterocyclic synthesis, and organocatalysis.

show abstract

Sequential one-pot and three-component reactions of an N-heterocyclic carbene to form 4-(1,2,4-triazol-5-ylidene)pyrrolidine-2,5-diones: a tandem umpolung/annulation sequence via deoxy-Breslow intermediates

Cited by 33 publications

References 71 publications

Enantioselective N‐Heterocyclic Carbene Catalysis by the Umpolung of α,β‐Unsaturated Ketones

Enantioselective N‐Heterocyclic Carbene Catalysis by the Umpolung of α,β‐Unsaturated Ketones

Triazaspirocycles: Occurrence, Synthesis, and Applications

Recent advances in neutral and anionic N-heterocyclic carbene – betaine interconversions. Synthesis, characterization, and applications

Contact Info

Product

Resources

About