Enantioselective synthesis of the tetrahydro-6H-benzo[c]chromenes via Domino Michael–Aldol condensation: control of five stereocenters in a quadruple-cascade organocatalytic multi-component reaction

Kotame, Prakash; Hong, Bor‐Cherng; Liao, Ju‐Hsiou

doi:10.1016/j.tetlet.2008.11.106

Cited by 134 publications

(51 citation statements)

References 64 publications

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“…42 Very recently, Hong et al have extended this methodology to the cascade oxa-Michael/Michael/Michael/aldol condensation reaction for the enantioselective synthesis of tetrahydro-6H-benzo[c]chromenes (Scheme 41). 43 The cascade sequence of the proposed mechanism starts in an analogous manner to that previously mentioned, although the first oxa-Michael step is followed by a second Michael addition to form the chromane unit. The intermediate X undergoes a new Michael attack of the nitro anion on to the a,b-unsaturated aldehydes, activated through an iminium ion with the diarylprolinol ether catalyst, followed by an intramolecular aldol reaction and subsequent elimination of water.…”

Section: Wang Et Al Have Recently Reported An Organocatalyzed Asymmementioning

confidence: 92%

Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

et al. 2010

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Section: Wang Et Al Have Recently Reported An Organocatalyzed Asymmementioning

confidence: 92%

Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

et al. 2010

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“…[140] Catalyst (S)-3 was also applied by Hong et al to induce a highly diastereo-and enantioselective quadruple-cascade oxa-Michael-Michael-Michael-aldol reaction, constructing four new bonds and five stereocenters in one step, which provided an expedited access to highly functionalized and almost enantiopure tetrahydro-6H-benzo[c]chromene 299. [141] This process was based on the reaction of 2-(E)-(2-nitrovinyl)-phenol 298 with cinnamaldehyde performed in the presence of an additive, such as acetic acid, and occurring through the iminium-enamine mode activation. As shown in Scheme 78, both the diastereo-and enantioselectivities were excellent, since they were found to be of up to > 94% de and > 99% ee, respectively.…”

Section: Michael Reaction Of Ab-unsaturated Aldehydesmentioning

confidence: 99%

Recent Developments in Asymmetric Organocatalytic Domino Reactions

2012

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Since about the year 2000, the research area of asymmetric organocatalysis has grown rapidly to become one of the most fascinating and current fields in organic chemistry. In the last years, asymmetric domino reactions have widely benefited from this fast-growing field, as exemplified by the development of an explosive number of novel and powerful asymmetric organocatalytic domino processes, which allowed the easy construction of complex chiral molecular architectures from simple materials with high yields and very often remarkable enantioselectivities in a metal-free environment. Indeed, the possibility to join two or more organocatalytic reactions in one asymmetric domino process has become a challenging goal for chemists, due to several advantages from economical and environmental points of view, avoiding costly protecting groups and time-consuming purification procedures after each step, for example. This review aims to update the latest developments of this hot and fascinating field, covering the literature since the beginning of 2009.

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“…The hypothesized mechanistic pathway depicted in Scheme 50, should account for the excellent reaction stereocontrol probably due to the first oxa-Michael addition while the resulting product presumably dictates the stereochemistry of the subsequent reactions [88].…”

Section: Cascade Reactionsmentioning

confidence: 99%

An Organocatalytic Approach to the Synthesis of Six-Membered Heterocycles

Gasperi¹,

Punzi²,

Migliorini³

et al. 2011

COC

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"""In the last few years, the new era of organocatalysis opened up an effective and efficient way to high yielding metal free, enantio- and diastereoselective reactions leading to six-membered heterocycles. This review provides an overview of the current achievements in the organocatalytic synthesis of these crucial building blocks. Ranging from hetero-Diels-Alder to cycloadditions, from one step cyclizations to cascade reactions, recent results offer new powerful tools to obtain six membered heterocycles with facile procedures in high yields and stereoselection, often leading to many new stereogenic centres in a single reaction. The total syntheses of natural products having heterocyclic ring formation as crucial stage, are also reported. When available, alternative supported organocatalysts have been examined""

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Enantioselective synthesis of the tetrahydro-6H-benzo[c]chromenes via Domino Michael–Aldol condensation: control of five stereocenters in a quadruple-cascade organocatalytic multi-component reaction

Cited by 134 publications

References 64 publications

Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

Asymmetric organocatalytic synthesis of six-membered oxygenated heterocycles

Recent Developments in Asymmetric Organocatalytic Domino Reactions

An Organocatalytic Approach to the Synthesis of Six-Membered Heterocycles

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