نتایج جستجو برای: β ketoesters

تعداد نتایج: 177597  

Journal: :Helvetica Chimica Acta 2021

The synthesis of spirocyclic amide acetals (33–93 %) has been achieved through Ru(II)-catalyzed condensations N-carbamate protected pyrrolidinones with metal carbenes derived from α-diazo-β-ketoesters. Thanks to the mildness diazo decomposition conditions induced by a 1 : combination [CpRu(MeCN)3][BArF] and 1,10-phenanthroline, formation sensitive products is possible. Full characterization thi...

Journal: :Journal of the American Chemical Society 2013
Wen-Bo Liu Corey M Reeves Scott C Virgil Brian M Stoltz

Highly congested vicinal stereocenters comprised of tertiary and all-carbon quaternary centers were generated via Ir-catalyzed asymmetric allylic alkylation of β-ketoesters. These catalytic reactions proceed in excellent yields with a broad scope on either reaction partner and with outstanding regio-, diastereo-, and enantiocontrol. Implementation of a subsequent Pd-catalyzed alkylation affords...

Journal: :Journal of the American Chemical Society 2016
Wen-Bo Liu Noriko Okamoto Eric J Alexy Allen Y Hong Kristy Tran Brian M Stoltz

A catalytic, enantioselective γ-alkylation of α,β-unsaturated malonates and ketoesters is reported. This strategy entails a highly regio- and enantioselective iridium-catalyzed α-alkylation of an extended enolate, and a subsequent translocation of chirality to the γ-position via a Cope rearrangement.

2014
Fei Zhou Tom G. Driver

The development of a lead-mediated α-arylation reaction between aryl azides and β-ketoesters or γ-lactams that facilitates the formation of 3H-indoles is disclosed. Twenty-five examples are included which demonstrate the generality of this reaction to access aryl azides bearing tetrasubstituted o-alkyl substituents. When paired with a Staudinger reduction, this reaction streamlines the synthesi...

Journal: :Organic & biomolecular chemistry 2015
Shengmei Guo Lin Lu Jiuhan Gong Zheng Zhu Feng Xu Zhenhong Wei Hu Cai

A copper-mediated tandem reaction of β-ketoesters/ketones with tertiary amines was achieved, which provides a simple and efficient approach to the synthesis of 2,3-dihydrofuran derivatives. In this tandem reaction, the tertiary amine not only offers the methylene moiety but also serves as the base.

Journal: :Symmetry 2016
Daniel Serrano Sánchez Alejandro Baeza Diego A. Alonso

Bifunctional chiral 2-aminobenzimidazole derivatives 1 and 2 catalyze the enantioselective stereodivergent α-chlorination of β-ketoesters and 1,3-diketone derivatives with up to 50% ee using N-chlorosuccinimide (NCS) or 2,3,4,4,5,6-hexachloro-2,5-cyclohexadien-1-one as electrophilic chlorine sources.

2011
Silke Dubberke Muhammad Abbas Bernhard Westermann

Enantiomerically highly enriched unsaturated β-ketoesters bearing a quaternary stereocenter can be utilized as building blocks for the synthesis of natural occurring terpenes, i. a., trisporic acid and its derivatives. An advanced building block has been synthesized in a short reaction sequence, which involves an oxidative allylic rearrangement initiated by pyridinium dichromate (PDC) as the ke...

Journal: :Molecules 2011
Huanan Hu Liangfu Song Qianqian Fang Junjun Zheng Zhiwei Meng Yiting Luo

A facile synthesis of potential acetylcholinesterase (AChE) inhibitors, the tacrine analogues 3a-p, has been accomplished by direct cyclocondensation of 1-aryl-4-cyano-5-aminopyrazole with β-ketoesters using tin(IV) chloride as catalyst. The structures of all the compounds have been confirmed by IR, ¹H- and ¹³C-NMR.

2012
Wen-Bin Yi Xin Huang Zijuan Zhang Dian-Rong Zhu Chun Cai Wei Zhang

A fluorous cinchona alkaloid ester has been developed as a chiral promoter for the asymmetric fluorination of β-ketoesters. It has comparable reactivity and selectivity to the nonfluorous versions of cinchona alkaloids and can be easily recovered from the reaction mixture by simple fluorous solid-phase extraction (F-SPE) and used for the next round of reaction without further purification.

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