An Organocatalytic Synthesis of <i>cis‐N</i>‐Alkyl‐ and <i>N</i>‐Arylaziridine Carboxylates

Bew, Sean P.; Carrington, Rachel; Hughes, David L.; Liddle, John; Pesce, Paolo

doi:10.1002/adsc.200900474

Cited by 20 publications

(5 citation statements)

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“…The synthesis of amine 15 deserves particular attention, because this compound is not efficiently formed in the presence of ruthenium porphyrins. In addition, the p -(MeO)C 6 H 4 (PMP) protecting group on the nitrogen atom can be easily removed, , yielding the corresponding free amino derivatives.…”

Section: Resultsmentioning

confidence: 99%

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

et al. 2015

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We report herein the synthesis of new glycoporphyrin ligands which bear a glucopyranoside derivative on each meso-aryl moiety of the porphyrin skeleton. The saccharide unit is directly conjugated to the porphyrin or a triazole spacer is placed between the carbohydrate and porphyrin ring. The obtained glycoporphyrin ligands were employed to synthesize cobalt(II), ruthenium(II), and iron-(III) complexes which were tested as catalysts of C−H bond aminations by organic azides. Two of the synthesized complexes were very efficient in promoting catalytic reactions, and the results achieved indicated that ruthenium and iron complexes show an interesting complementary catalytic activity in several amination reactions. The eco-friendly iron catalyst displayed very good chemical stability in catalyzing the amination reaction for three consecutive runs without losing catalytic activity.

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Section: Resultsmentioning

confidence: 99%

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

et al. 2015

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“…We report the first application of the fluoronium cation, i.e., F + derived from an N-fluoroheterocyclic salt, as a convenient, highly effective organocatalyst for aziridine synthesis. As part of our ongoing investigation toward new synthetic routes to aziridines, we wanted to develop a single organocatalytic entity capable of generating both N -aryl- and NH-C 2,3 -disubstituted aziridines. We demonstrate that N-fluoroheterocyclic salts are powerful, versatile organocatalysts that mediate the reaction between ethyl diazoacetate and N -arylimines or N -trimethysilylimines such that a diverse range of N -aryl-C 2,3 -disubstituted aziridines or NH-C 2,3 -disubstituted aziridines are generated in good yields and often with good stereoselectivities.…”

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Organocatalytic Aziridine Synthesis Using F⁺ Salts

Bew

Ashford²,

Fairhurst³

et al. 2009

Org. Lett.

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“…established chiral BINOL phosphoric acids [p K a ≈13 (CH 3 CN)] activate aldimines (derived from, specifically, arylglyoxals and p ‐anisidine) and react with ethyl diazoacetate (EDA) affording cis ‐aziridines in 92–97 % ee . Similarly, other Brønsted acids and pyridinium triflate activate a diverse array of imines, including for example, 2‐pyridyl derived 5 , enabling the presumed imminium ion‐pair (not shown) to react with EDA and afford cis ‐ rac ‐aziridine ( 8 , 83 % yield) (Scheme ) . With these racemic studies complete our focus shifted to developing a substrate enhanced and diverse, multi‐component asymmetric aza‐Darzens reaction.…”

Section: Methodsmentioning

confidence: 99%

Chiral Brønsted Acid‐Catalyzed Asymmetric Synthesis of N‐Aryl‐cis‐aziridine Carboxylate Esters

et al. 2017

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We report amulti-component asymmetric Brønsted acid-catalyzed aza-Darzens reaction whichi sn ot limited to specific aromatic or heterocyclic aldehydes.I ncorporating alkyld iazoacetates and, important for high ees, ortho-tertbutoxyaniline our optimized reaction (i.e.solvent, temperature and catalyst study) affords excellent yields (61-98 %) and mostly > 90 %o ptically active cis-aziridines.( + +)-Chloramphenicol was generated in 4s teps from commercial starting materials.Atentative mechanism is outlined.Such is the versatility of organocatalysis and its ability to mediate ap lethora of diverse reaction types [1] it is,n ow,a n indispensable "tool" in the synthetic chemists "toolbox". [2] Indeed, improving atom-and reaction-efficiencyi sakey driver to developing new reactions and protocols;i nt his context organocatalysis has demonstrated its importance by efficiently mediating many different convergent reactions or multi-component syntheses.T he work here supports these aspects by generating structure and function-diverse motifs via fewer synthetic, isolation and purification steps.Optically active aziridines have many diverse uses, especially as key intermediates [3] "on route" to important "secondary" products for example, a-/b-amino acids,p olymers,azasugars,auxilaries,oxazolidinones,imidazolidines, blactams and pyrrolidines.F urther applications include synthesis of non-aziridine containing bioactive compounds for example,k ainoids,( À)-mesembrine,( À)-platynesine,a ctinomycin and feldamycin, in addition to synthetic bioactive aziridines for example,NSC676892 as well as natural products for example,azinomycin and maduropeptide. [4] Using aB INOL N-triflylphosphoramide Brønsted acid a6 1-98 %y ielding asymmetric aza-Darzens reaction affords N-aryl-cis-aziridines in, mostly,9 0-99 % ee.T he reaction is straightforward to set up and has minimal requirements for strictly anhydrous or anaerobic conditions,f urthermore it does not require organocatalyst pre-generation or activation, or an "activated" arylglyoxal starting material. Exploiting the protocol synthesis of aziridines based on 4 uses readily generated or commercially available aldehydes (1), amines (2)a nd alkyl diazoacetates (3,Scheme 1).Activating the C = Nb ond of an imine with aB INOL phosphoric acid [5] lowers its LUMO energy and generates an imminium ion pair that can, but not always will, react with an ucleophile.S eminal work by Akiyama et al. established chiral BINOL phosphoric acids [pK a % 13 (CH 3 CN) [6] ]a ctivate aldimines (derived from, specifically,arylglyoxals and panisidine) and react with ethyl diazoacetate (EDA) affording cis-aziridines in 92-97 % ee.[7] Similarly,o ther Brønsted acids [8] and pyridinium triflate activate ad iverse array of imines,i ncluding for example,2 -pyridyl derived 5,e nabling the presumed imminium ion-pair (not shown) to react with EDAa nd afford cis-rac-aziridine (8,8 3% yield) (Scheme 2).[9] With these racemic studies complete our focus shifted to developing asubstrate enhanced and diverse, mult...

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An Organocatalytic Synthesis of cis‐N‐Alkyl‐ and N‐Arylaziridine Carboxylates

Cited by 20 publications

References 78 publications

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

Organocatalytic Aziridine Synthesis Using F⁺ Salts

Chiral Brønsted Acid‐Catalyzed Asymmetric Synthesis of N‐Aryl‐cis‐aziridine Carboxylate Esters

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An Organocatalytic Synthesis of cis‐N‐Alkyl‐ and N‐Arylaziridine Carboxylates

Cited by 20 publications

References 78 publications

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

Glycoporphyrin Catalysts for Efficient C–H Bond Aminations by Organic Azides

Organocatalytic Aziridine Synthesis Using F+ Salts

Chiral Brønsted Acid‐Catalyzed Asymmetric Synthesis of N‐Aryl‐cis‐aziridine Carboxylate Esters

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Organocatalytic Aziridine Synthesis Using F⁺ Salts