Nucleophilic Arylation of <i>N</i>,<i>O</i>‐Ketene Acetals with Triaryl Aluminum Reagents: Access to α‐Aryl Amides through an Umpolung Process

Takeda, Norihiko; Futaki, Erika; Kobori, Yukiko; Ueda, Masafumi; Miyata, Okiko

doi:10.1002/anie.201708665

Cited by 39 publications

(23 citation statements)

References 72 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Recently, the scope expanded to include α‐additions of heteroatom nucleophiles, such as N‐ , O‐ , S‐ functionalizations ,. Although introduction of a new stereogenic center has been successful with auxiliary methods,, a catalytic enantioselective version would constitute a major synthetic challenge.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Organocatalytic Oxidative Functionalizations of Alkynes

Patil

Shin

2018

Asian J Org Chem

View full text Add to dashboard Cite

The catalytic oxidation of alkynes has traditionally belonged to the domain of transition metal catalysis. Recently, several promising organocatalytic methods have been developed, leading to selective oxidative transformations of alkynes. For example, ynamides, because of their electron-rich alkynes, are ideal candidates for Brønsted acid-catalysis. A closely related keteniminium intermediate could also be accessed via amide activation. A particularly interesting aspect in this regard is a facile access to umpolung enolates, which would enable novel disconnections with complementary selectivity to traditional methods. Scheme 1. Carbene reactivity: metal vs. Brønsted acid catalyst. Scheme 2. Routes for the generation of keteniminium ions. . Trapping vinyl cation with sulfoxide. Scheme 18. Iodine-Catalyzed oxidation of ynamides: a chemoselectivity change.

show abstract

Section: Discussionmentioning

confidence: 99%

“…Recently, the same group demonstrated a different type of umpolung chemistry using hydroxamic acid derivatives . The cyclic hydroxamic acid derivative 27 was in‐situ functionalized into ketene N,O‐ acetal 28 which subsequently underwent intermolecular nucleophilic addition of Ph 3 Al.…”

Section: Intermolecular Addition Of Nucleophilesmentioning

confidence: 99%

Organocatalytic Oxidative Functionalizations of Alkynes

Patil

Shin

2018

Asian J Org Chem

View full text Add to dashboard Cite

show abstract

“…114,115 A related elegant example was recently disclosed by the Miyata group, employing isoxazolidine amides (206) in combination with organoaluminium nucleophiles for the a-arylation of amides (Scheme 28c). 116 Moreover, chemoselective amide a-oxidation with N-oxides (employed for the transformation of linear amides) and TEMPO (preferred for branched and hindered amides) has been…”

Section: Review Articlementioning

confidence: 99%

Amide activation: an emerging tool for chemoselective synthesis

et al. 2018

View full text Add to dashboard Cite

It is textbook knowledge that carboxamides benefit from increased stabilisation of the electrophilic carbonyl carbon when compared to other carbonyl and carboxyl derivatives. This results in a considerably reduced reactivity towards nucleophiles. Accordingly, a perception has been developed of amides as significantly less useful functional handles than their ester and acid chloride counterparts. However, a significant body of research on the selective activation of amides to achieve powerful transformations under mild conditions has emerged over the past decades. This review article aims at placing electrophilic amide activation in both a historical context and in that of natural product synthesis, highlighting the synthetic applications and the potential of this approach.

show abstract

“…An asymmetric version of this reaction was devised by using a chiral isoxazolidine. 50 In 2017 Miyata and co-workers 51 adapted this approach to accomplish umpolung -arylation of amides (Scheme 11). In this method, the N-acylisoxazolidine 12 is silylated to form the N-oxyenamine 13, which then reacts with orga- A substantial disadvantage of these two methods is the need for a strong Lewis acid [aluminum(III)] to assist the breakage of isoxazolidine ring.…”

Section: Synpacts Syn Lettmentioning

confidence: 99%

Umpolung of Enamines: An Overview on Strategies and Synthons

Sukhorukov

2020

Synlett

View full text Add to dashboard Cite

Umpolung strategies are of considerable interest to organic chemists because they provide alternative synthetic routes to those imposed by the natural polarity of classical synthons. Reverse-polarity reactions of aldehydes, α,β-unsaturated carbonyl compounds, and imines are deeply embedded in the methodology of organic synthesis. In recent years, umpolung of enols and enamines has received much attention as a novel strategy to access α-substituted ketones. Here, state-of-the-art approaches to umpolung of enamine reactivity are discussed, with a particular focus on recent developments in this field from the author’s research group.1 Introduction2 Approaches toward Umpolung of Enamines3 Umpolung of Enamines through Single-Electron Oxidation4 Azadienes as Synthetic Equivalents of Enamine Umpolung Synthons5 Enamines Possessing a Leaving Group at the Nitrogen Atom6 Enamines Possessing a Directing Group at the Nitrogen Atom7 Summary and Outlook

show abstract

Nucleophilic Arylation of N,O‐Ketene Acetals with Triaryl Aluminum Reagents: Access to α‐Aryl Amides through an Umpolung Process

Cited by 39 publications

References 72 publications

Organocatalytic Oxidative Functionalizations of Alkynes

Organocatalytic Oxidative Functionalizations of Alkynes

Amide activation: an emerging tool for chemoselective synthesis

Umpolung of Enamines: An Overview on Strategies and Synthons

Contact Info

Product

Resources

About