Imine and iminium precursors as versatile intermediates in enantioselective organocatalysis

Kataja, Antti O.; Masson, Géraldine

doi:10.1016/j.tet.2014.06.101

Cited by 64 publications

(20 citation statements)

References 201 publications

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“…After preparing precursors 33 b and 33 c,t he authors synthesized compounds 35 and 36,r espectively intermediates in the syntheses of (+ +)-catharanthine [26] and (+ +)-allocatharanthine. [27] CÀCBond Formation by Enantioselective Nucleophilic Additions onto Imines and Carbonyl Derivatives [28] a-Stereogenic amines are exceptionally widespread molecular motifsi nn ature but the diversity of the considered structures can make their synthesis arduous. Nonetheless,e nantioselective CÀCb ond formation by nucleophilic addition onto imines constitutes an obvious disconnection.…”

Section: Double Michaeladdition Cascadementioning

confidence: 99%

Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals

Merad

Lalli

Bernadat³

et al. 2017

Chemistry A European J

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146

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Synthesis of biologically active molecules (whether at laboratory or industrial scale) remains a highly appealing area of modern organic chemistry. Nowadays, the need to access original bioactive scaffolds goes together with the desire to improve synthetic efficiency, while reducing the environmental footprint of chemical activities. Long neglected in the field of total synthesis, enantioselective organocatalysis has recently emerged as an environmentally friendly and indispensable tool for the construction of relevant bioactive molecules. Notably, enantioselective Brønsted acid catalysis has offered new opportunities in terms of both retrosynthetic disconnections and controlling stereoselectivity. The present report attempts to provide an overview of enantioselective total or formal syntheses designed around Brønsted acid-catalyzed transformations. To demonstrate the versatility of the reactions promoted and the diversity of the accessible motifs, this Minireview draws a systematic parallel between methods and retrosynthetic analysis. The manuscript is organized according to the main reaction types and the nature of newly-formed bonds.

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Section: Double Michaeladdition Cascadementioning

confidence: 99%

Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals

Merad

Lalli

Bernadat³

et al. 2017

Chemistry A European J

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146

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“…In addition, the elimination byproduct EtOH could also have a deleterious effect on the reactivity and/or stereoselectivity by a competing hydrogen bonding. Our examination of the literature revealed no precedents of chiral base-catalysed generation of N -Boc imines from N -Boc- N , O -acetals 28 . Despite these challenges, chiral bases, (DHQD) 2 PHAL (hydroquinidine 1,4-phthalazinediyl diether) 29 , quinine and cinchonidine, were preliminarily tested in the model reaction of 1a and 2a .…”

Section: Resultsmentioning

confidence: 84%

Asymmetric synthesis of syn-propargylamines and unsaturated β-amino acids under Brønsted base catalysis

Wang

Zhu

et al. 2015

Nat Commun

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Propargylamines are important intermediates for the synthesis of polyfunctional amino derivatives and natural products and biologically active compounds. The classic method of synthesizing chiral propargylamines involves the asymmetric alkynylation of imines. Here, we report a significant advance in the catalytic asymmetric Mannich-type synthesis of propargylamines through catalytic asymmetric addition of carbon nucleophiles to C-alkynyl imines, culminating in a highly syn-selective catalytic asymmetric Mannich reaction of C-alkynyl imines that provide syn-configured propargylamines with two adjacent stereogenic centres and a transition metal-free organocatalytic asymmetric approach to β-alkynyl-β-amino acids with high efficiency and practicality, via a chiral Brønsted base-catalysed asymmetric Mannich-type reaction of in situ generated challenging N-Boc C-alkynyl imines from previously unreported C-alkynyl N-Boc-N,O-acetals, with α-substituted β-keto esters and less-acidic malonate (thio)esters as nucleophiles, respectively. A catalytic activation strategy is also disclosed, which may have broad implications for use in catalysis and synthesis.

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“…Although synthetic transformations based on 3‐indolyl carbinols are well documented, the chemistry of 2‐indolyl carbinols is much less developed . We envisioned that a 1 H ‐indol‐2‐yl carbinol 4 could be readily converted into a reactive 2‐methide‐2 H ‐indole 5 upon dehydration with a chiral phosphoric acid.…”

Section: Figurementioning

confidence: 99%

“…Although synthetic transformationsb ased on 3-indolyl carbinols are well documented, [11] the chemistry of 2-indolyl carbinols is much less developed. [12,13] We envisioned that a1 Hindol-2-yl carbinol 4 could be readily converted into ar eactive 2-methide-2H-indole 5 upon dehydration with ac hiral phosphoric acid.T he hydrogen-bonded 2-methide-2H-indole 5 may then engage 2-vinylindole 6 in aw ell-organized transition state through additional hydrogen bonding and forge the en- [a] Dr.K.B era, Prof. Dr.C .S chneider Institut für Organische Chemie, UniversitätL eipzig Johannisallee 29,0 4103 Leipzig (Germany) E-mail:schneider@chemie.uni-leipzig.de suing [3+ +2]-cycloaddition (Scheme 1).…”

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confidence: 99%

Brønsted Acid Catalyzed [3+2]‐Cycloaddition of 2‐Vinylindoles with In Situ Generated 2‐Methide‐2H‐indoles: Highly Enantioselective Synthesis of Pyrrolo[1,2‐a]indoles

Bera

Schneider

2016

Chemistry A European J

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Pyrrolo[1,2-a]indoles are privileged structural elements of many natural products and pharmaceuticals. An efficient one-step process for their highly diastereo- and enantioselective synthesis, comprising a direct [3+2]-cycloaddition, has been developed. A chiral BINOL-derived phosphoric acid catalyzes the reaction of in situ-generated 2-methide-2H-indoles with 2-vinylindoles, furnishing the target products incorporating three contiguous stereogenic centers as single diastereoisomers and with excellent yields and enantioselectivities.

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Imine and iminium precursors as versatile intermediates in enantioselective organocatalysis

Cited by 64 publications

References 201 publications

Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals

Enantioselective Brønsted Acid Catalysis as a Tool for the Synthesis of Natural Products and Pharmaceuticals

Asymmetric synthesis of syn-propargylamines and unsaturated β-amino acids under Brønsted base catalysis

Brønsted Acid Catalyzed [3+2]‐Cycloaddition of 2‐Vinylindoles with In Situ Generated 2‐Methide‐2H‐indoles: Highly Enantioselective Synthesis of Pyrrolo[1,2‐a]indoles

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