Efficient Method for the Synthesis of Optically Active 2‐Amino‐2‐chromene Derivatives <i>via</i> One‐Pot Tandem Reactions

Xie, Jian‐Hua; Huang, Xin; Fan, Liping; D, Xu; Li, Xinsheng; Su, Hong; Wen, Yi‐Hang

doi:10.1002/adsc.200900579

Cited by 95 publications

(28 citation statements)

References 86 publications

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“…Although the enantioselectivity of the developed tandem Michael addition/Thorpe-Ziegler type reaction was found to be dependent on the reaction conditions and fine structure catalysts, cupreine (367) were identified as the best catalyst not only in the common twocomponent reaction, but also in both the three-and four-component synthesis of 6-amino-5-cyanodihydropyrano[2,3-c]pyrazoles, achieving high enantiomeric excess (up to 99% ee) and yield (89%) (Scheme 56). An interesting improvement of such a strategy, which elegantly coupled the activation modes of both hydrogen-bond donors and iminium organocatalysis, was quite recently reported by Xie's group [98]. The synergic action of both 9-amino-9-deoxyepiquinine (369) and 1,1'-binaphth-2,2'-diyl hydrogen phosphate (370) allowed to accomplish the synthesis of a quite broad range of optically active 2-amino-2-chromene derivatives 371 and 372 in good enantioselectivity (94% ee) and yield (21-76%) (Scheme 57).…”

Section: Cascade Reactionsmentioning

confidence: 98%

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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Section: Cascade Reactionsmentioning

confidence: 98%

An Organocatalytic Approach to the Synthesis of Six-Membered Heterocycles

Gasperi¹,

Punzi²,

Migliorini³

et al. 2011

COC

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“…[70] Indeed, the corresponding 5-hydroxy-3-arylisoxazolidines 132a-e were achieved in excellent yields of up to 94% and with moderate to high enantioselectivities (64 to > 99% ee), as shown in highly functionalized chiral 2-amino-2-chromene derivatives 133a-e by this type of domino reaction occurring between a,b-unsaturated enones, such as 2-hydroxybenzalacetones 134a-e, and malononitrile. [71] This novel process was catalyzed by a Cinchona alkaloid-derived primary amine, such as 9-amino-9-deoxyepiquinine 135, in combination with (R)-1,1'-binaphth-2,2'-diyl hydrogen phosphate ((R)-BDHP). As shown in Scheme 36, excellent enantioselectivities of up to 96% ee were obtained in combination with high yields of up to 84% for a range of b-substituted 2-hydroxybenzalacetones 134a-e.…”

Section: Domino Michael-intramolecular Heterocyclization Reactionsmentioning

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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“…Moreover, harsh conditions were required in some reported synthetic methods such as reflux, microwave or electrolysis [1][2][3]. More recently, some new routes were reported to synthesize 2-amino-4H-chromenes through the domino Michael addition/intramolecular cyclization reactions from readily available 2-hydroxychalcones with malononitrile, employing a small organic molecule [9-amino-9-deoxyepiquinine in combination with (R)-1,1'-binaphth-2,2'-diylhydrogen phosphate] or a basic salt (NaHCO 3 ) as a catalyst, respectively [20,21]. Considering the importance of 2-amino-4H-chromenes in both biological and chemical fields, the development of environmentally friendly catalysts and mild conditions to realize this important transformation is still desirable.…”

Section: Introductionmentioning

confidence: 99%