Asymmetric Synthesis of 4‐Amino‐4<i>H</i>‐Chromenes by Organocatalytic Oxa‐Michael/Aza‐Baylis–Hillman Tandem Reactions

Alemán, José V.; Núñez, Alberto; Marzo, Leyre; Marcos, Vanesa; Alvarado, Cuauhtémoc; Ruano, José Luis Garcı́a

doi:10.1002/chem.201001293

Cited by 79 publications

(26 citation statements)

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“…Alkynals are known to be a challenging class of electrophiles in asymmetric catalysis because they would adopt different structures and geometry51. As such, in contrast to these widely reported iminium activated enal systems, the organocatalytic enantioselective transformation involving alkynal remains underexplored5253545556. In this context, Wang and co-workers reported the elegant work53 involving a domino iminium-allenamine process to control the stereoselectivity far from the β -position on the alkynal.…”

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confidence: 99%

Organocatalytic atroposelective synthesis of axially chiral styrenes

et al. 2017

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Axially chiral compounds are widespread in biologically active compounds and are useful chiral ligands or organocatalysts in asymmetric catalysis. It is well-known that styrenes are one of the most abundant and principal feedstocks and thus represent excellent prospective building blocks for chemical synthesis. Driven by the development of atroposelective synthesis of axially chiral styrene derivatives, we discovered herein the asymmetric organocatalytic approach via direct Michael addition reaction of substituted diones/ketone esters/malononitrile to alkynals. The axially chiral styrene compounds were produced with good chemical yields, enantioselectivities and almost complete E/Z-selectivities through a secondary amine-catalysed iminium activation strategy under mild conditions. Such structural motifs are important precursors for further transformations into biologically active compounds and synthetic useful intermediates and may have potential applications in asymmetric synthesis as olefin ligands or organocatalysts.

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confidence: 99%

Organocatalytic atroposelective synthesis of axially chiral styrenes

et al. 2017

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“…Two years later from MacMillan's work, Wang,4 and Alem an 5 published the asymmetric synthesis of chromenes derivatives. In both cases, the authors used salicylaldehyde derivatives as starting materials.…”

Section: Alkynals Under Iminium Catalysismentioning

confidence: 99%

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

et al. 2014

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“…The authors have proposed the mechanism depicted in Scheme 56, in which enamine 205 derived from the cyclic ketone and the catalyst added to the (E)-2-nitroallylic acetate to give the corresponding Michael product which was further submitted to dehydratation to produce intermediate 206. ring between alkynals 208a-e and salicyl N-tosylimine 209. [104] This highly enantioselective reaction was catalyzed by chiral diarylprolinol silyl ether 129, which was supposed to activate alkynals 208a-e, forming iminium intermediates 210, that underwent an oxaMichael addition with salicyl N-tosylimine 209. The resulting allenamine intermediate 211 reacted with the imine in an intramolecular fashion leading to the final 4-amino-4H-chromenes 212a-e and regenerating the catalyst.…”

Section: Other Domino Reactions Initiated By the Michael Reactionmentioning

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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Asymmetric Synthesis of 4‐Amino‐4H‐Chromenes by Organocatalytic Oxa‐Michael/Aza‐Baylis–Hillman Tandem Reactions

Abstract: In the Communication by J. Alemµn et al., the wrong journal was cited in reference [11i], the correct reference is included below. We apologize for this oversight.[11] i) C. Grondal, M. Jeanty, D. Enders, Nat. Chem.

Cited by 79 publications

References 76 publications

Organocatalytic atroposelective synthesis of axially chiral styrenes

Organocatalytic atroposelective synthesis of axially chiral styrenes

Organocatalytic transformations of alkynals, alkynones, propriolates, and related electron-deficient alkynes

Recent Developments in Asymmetric Organocatalytic Domino Reactions

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