Organocatalytic formal [5+1] annulation: diastereoselective cascade synthesis of functionalized six-membered spirocyclic indane-1,3-diones/oxindoles via Michael–aldol reaction

Roy, Suparna; Amireddy, Mamatha; Chen, Kwunmin

doi:10.1016/j.tet.2013.07.084

Cited by 39 publications

(11 citation statements)

References 57 publications

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“…As expected, pseudoenantiomeric catalysts (II and V)a fforded opposite enantiomers (Table 1, entries 4a nd 7). The crucial role in determining the enantioselectivity played by the thiourea moiety was confirmed by employing alkaloids X and XI (entries [12][13]. Althoughabifunctional system was still present, these catalysts exertedl ower levels of stereocontrol (66-73 % ee).…”

Section: Resultsmentioning

confidence: 95%

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Highly Stereoselective [4+2] and [3+2] Spiroannulations of 2‐(2‐Oxoindolin‐3‐ylidene)acetic Esters Catalyzed by Bifunctional Thioureas

Monari

Montroni

Nitti

et al. 2015

Chemistry A European J

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A new Michael-Michael cascade reaction between 2-(2-oxoindolin-3-ylidene)acetic esters 1 and nitroenoates 2, catalyzed by bifunctional thioureas, is investigated. The combination of the two Michael reactions results in a novel and facile [4+2] or [3+2] spiroannulation process, which is characterized by the following features: 1) two carbon-carbon bonds and four stereocenters, including a quaternary spiro carbon, are formed under mild conditions; 2) an unprecedented and stereochemically defined substitution pattern on the spirocarbocyclic unit is obtained; 3) the double-bond configuration of the donor-acceptor nitroenoate 2 determines the absolute configuration of the spiro center, whereas the remaining stereocenters are formed under control of the catalyst. The effect on the final stereochemical outcome of structural variations of each starting material, catalyst, and experimental conditions is analyzed in detail. In particular, the use of specifically designed chiral nitroenoates enables diverse polyfunctional spirocyclohexane derivatives containing six consecutive stereogenic centers to be constructed. To our knowledge, this is the first asymmetric organocatalytic strategy enabling both five- and six-membered β-nitro spirocarbocyclic oxindoles.

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Section: Resultsmentioning

confidence: 95%

“…1a nd 2). [10][11][12] Moreover,t he synthetic approachi sa lmost invariably based on the use of nitroalkenes as Michael acceptors( Scheme 1, Eq. 1).…”

Section: Introductionmentioning

confidence: 99%

Highly Stereoselective [4+2] and [3+2] Spiroannulations of 2‐(2‐Oxoindolin‐3‐ylidene)acetic Esters Catalyzed by Bifunctional Thioureas

Monari

Montroni

Nitti

et al. 2015

Chemistry A European J

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“…[17] This is another strategy to construct six-membered spirocyclic benzofuran-2-ones. In ethyl acetate at ambient temperature, quinine-derived thiourea 14 was verified to be an effective catalyst to promote this reaction.…”

Section: Benzofuran-2(3h)-ones As Substratesmentioning

confidence: 99%

“…In 2013, Chen’s group developed an organocatalytic formal [5+1] annulation 17. This is another strategy to construct six‐membered spirocyclic benzofuran‐2‐ones.…”

Section: Synthetic Strategiesmentioning

confidence: 99%

Catalytic Asymmetric Synthesis of Chiral Benzofuranones

Cheng

2014

Adv Synth Catal

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The chiral benzofuranone structural motif is a prominent feature in many natural products, which exhibit a broad range of biological and pharmaceutical activities. In the past few years, a survey of chiral benzofuranone derivatives based on asymmetric catalysis reveals an increasing number of papers, which reflects the latest achievements to facilitate the synthesis of sufficient quantities of related compounds as potential medicinal agents and biological probes. Recent advances in this area are summarized and classified according to the structure of the starting substrate.

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“…The vinylogous MBH (Rauhut-Currier, RC) reaction of nitroalkenes 14 and its applications for the synthesis of novel carbocyclic and heterocyclic scaffolds have also been of interest to us. We and others have employed RC adducts of nitroalkenes for the synthesis of functionalized pyrazoles, 15 decalins, 16 cycloalkanones, 17 spirocycles 18 and bridged heterobicyclics such as epibatidine. 19 The reactivity prole of a representative RC adduct 6, derived from the imidazole/LiCl mediated RC reaction of nitroalkene with MVK, is outlined in Scheme 2a.…”

mentioning

confidence: 99%

One-pot regioselective synthesis of functionalized and fused furans from Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

et al. 2015

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Highly functionalized and fused furans have been synthesized via cascade reactions of Morita-BaylisHillman and Rauhut-Currier adducts of nitroalkenes with active methylene compounds. The reactions involving S N 2 0 -intramolecular Michael addition or Michael addition-intra-molecular nucleophilic substitution take place in a regioselective manner to afford synthetically and biologically useful furans in moderate to good yields.

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Organocatalytic formal [5+1] annulation: diastereoselective cascade synthesis of functionalized six-membered spirocyclic indane-1,3-diones/oxindoles via Michael–aldol reaction

Cited by 39 publications

References 57 publications

Highly Stereoselective [4+2] and [3+2] Spiroannulations of 2‐(2‐Oxoindolin‐3‐ylidene)acetic Esters Catalyzed by Bifunctional Thioureas

Highly Stereoselective [4+2] and [3+2] Spiroannulations of 2‐(2‐Oxoindolin‐3‐ylidene)acetic Esters Catalyzed by Bifunctional Thioureas

Catalytic Asymmetric Synthesis of Chiral Benzofuranones

One-pot regioselective synthesis of functionalized and fused furans from Morita–Baylis–Hillman and Rauhut–Currier adducts of nitroalkenes

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