Recent Developments in Asymmetric Alkynylation of Imines

Blay, Gonzalo; Monleón, Alicia; Pedro, José R.

doi:10.2174/138527209789177734

Cited by 97 publications

(28 citation statements)

References 54 publications

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“…[69] Indeed, many transition-metal complexes, including gold complexes, are known to catalyze the addition of terminal alkynes to enamines, thereby affording propargyl amines. [96] In marked contrast, CAAC 3 Au+ efficiently mediates the catalytic coupling of enamines and terminal alkynes to yield allenes with the loss of imines. Mono-, di-, and trisubstituted enamines can be used, as well as aryl-, alkyl-, and trimethylsilyl-substituted terminal alkynes.…”

Section: Gold-caac Complexesmentioning

confidence: 99%

Stable Cyclic Carbenes and Related Species beyond Diaminocarbenes

2010

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The success of homogeneous catalysis can be attributed largely to the development of a diverse range of ligand frameworks that have been used to tune the behavior of various systems. Spectacular results in this area have been achieved using cyclic diaminocarbenes (NHCs) as a result of their strong σ-donor properties. Although it is possible to cursorily tune the structure of NHCs, any diversity is still far from matching their phosphorus-based counterparts, which is one of the great strengths of the latter. A variety of stable acyclic carbenes are known, but they are either reluctant to bind metals or they give rise to fragile metal complexes. During the last five years, new types of stable cyclic carbenes, as well as related carbon-based ligands (which are not NHCs), and which feature even stronger σ-donor properties have been developed. Their synthesis and characterization as well as the stability, electronic properties, coordination behavior, and catalytic activity of the ensuing complexes are discussed, and comparisons with their NHC cousins are made.

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Section: Gold-caac Complexesmentioning

confidence: 99%

Stable Cyclic Carbenes and Related Species beyond Diaminocarbenes

2010

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“…[20] Because of the low stability of most α-imino esters, however, their synthesis, purification, and handling can be difficult. [21] For this reason, relatively stable N-para-methoxyphenyl-substituted (N-PMP-substituted) imino esters are often used as substrates for the addition reactions of alkynes.…”

Section: Addition To N-aryl and N-acyl Iminesmentioning

confidence: 99%

“…Chan's group developed the addition of alkyl acetylenes 21a and phenylacetylene 21b to N-PMP-substituted ethyl glyoxylate imine (20) under Ag I (10 mol-%, Scheme 1) catalysis. [22] Among the examined catalysts, AgOTf (OTf = trifluoromethanesulfonate), AgNO 3 , AgPF 6 , and AgClO 4 showed acceptable activity, whereas AgOAc was less effective.…”

Section: Addition To N-aryl and N-acyl Iminesmentioning

confidence: 99%

Synthesis of α‐Ethynyl Glycines

Boļšakova

Jirgensons

2016

Eur J Org Chem

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α-Ethynyl glycine derivatives have a high potential for functionalization by derivatization of the amino acid or acetylene moiety, and, as a result, are important intermediates in the construction of biologically active compounds, including natural products. The main methods for the synthesis of ethynyl glycines and glycinols can be divided into six different transformations: (a) homologations of serinal derivatives, (b) nucleophilic alkynylations of α-imino esters/alcohols or their precur-

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“…[69] Viele Übergangsme-tallkomplexe, darunter auch Goldkomplexe, katalysieren die Addition von terminalen Alkinen an Enamine zu Propargylaminen. [96] Im Gegensatz dazu vermittelt CAAC [66,97] von diesen erwies sich aber keiner als wirkungsvoll, wenn NH 3 als Aminkomponente eingesetzt wurde.…”

Section: Caac-goldkomplexeunclassified

Stabile cyclische Carbene und verwandte Spezies jenseits der Diaminocarbene

2010

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Der Erfolg der homogenen Katalyse kann hauptsächlich der Entwicklung einer breiten Palette von Ligandengerüsten zugeschrieben werden, die vielfach genutzt wurden, um das Verhalten von Katalysatorsystemen gezielt abzustimmen. Spektakuläre Ergebnisse auf diesem Gebiet wurden mit cyclischen Diaminocarbenen, den so genannten N‐heterocyclischen Carbenen (NHCs), erzielt, die sich vor allem durch ihr starkes σ‐Donorverhalten auszeichnen. Obwohl sich die Strukturen der NHCs recht einfach modifizieren lassen, erreichen sie bei weitem nicht die Vielfalt etwa der Phosphorliganden. Auch eine große Zahl an stabilen acyclischen Carbenen ist bekannt, diese koordinieren aber entweder nur schlecht an Metalle oder führen zur Bildung sehr empfindlicher Metallkomplexe. In den letzten fünf Jahren wurden neue Arten stabiler Carbene und verwandter C‐Liganden entwickelt – bei denen es sich nicht um NHCs handelt –, die noch stärkere σ‐Donoreigenschaften aufweisen. In diesem Aufsatz beschreiben wir die Synthese, die Charakterisierung, die Stabilität, die elektronischen Eigenschaften, das Koordinationsverhalten und die katalytische Aktivität der daraus hergestellten Komplexe und stellen Vergleiche mit verwandten NHC‐Spezies an.

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Recent Developments in Asymmetric Alkynylation of Imines

Cited by 97 publications

References 54 publications

Stable Cyclic Carbenes and Related Species beyond Diaminocarbenes

Stable Cyclic Carbenes and Related Species beyond Diaminocarbenes

Synthesis of α‐Ethynyl Glycines

Stabile cyclische Carbene und verwandte Spezies jenseits der Diaminocarbene

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