Trans-Selective Asymmetric Aziridination of Diazoacetamides and <i>N</i>-Boc Imines Catalyzed by Axially Chiral Dicarboxylic Acid

Hashimoto, Takuya; Uchiyama, Nanase; Maruoka, Keiji

doi:10.1021/ja805635c

Cited by 133 publications

(68 citation statements)

References 34 publications

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“…4 Changing the nucleophile to a secondary diazoacetamide reverses the diastereoselectivity and trans -aziridines can be selectively formed. 5,6 Enamine formation ( 6 ) typically accompanies all these reaction modes to a greater or lesser degree. A diazonium ion 3 , resulting from the initial carbon-carbon bond forming event, is assumed to be the common intermediate that partitions into these three pathways as shown in Scheme 1.…”

Section: Introductionmentioning

confidence: 99%

Isotope Effects and Mechanism of the Asymmetric BOROX Brønsted Acid Catalyzed Aziridination Reaction

2013

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The mechanism of the chiral VANOL-BOROX Brønsted acid catalyzed aziridination reaction of imines and ethyldiazoacetate has been studied using a combination of experimental kinetic isotope effects and theoretical calculations. A stepwise mechanism where reversible formation of a diazonium ion intermediate precedes rate-limiting ring-closure to form the cis-aziridine is implicated. A revised model for the origin of enantio- and diastereoselectivity is proposed based on relative energies of the ring closing transition structures.

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Section: Introductionmentioning

confidence: 99%

Isotope Effects and Mechanism of the Asymmetric BOROX Brønsted Acid Catalyzed Aziridination Reaction

2013

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“…28 The optimal chiral catalyst to realize highly enantioselective trans-aziridination was 3,3¤-dimesityl axially chiral dicarboxylic acid (R)-42, with which a variety of trans-selective disubstituted aziridines could be obtained with high enantioselectivities (Scheme 32). 33 Following our report, Wulff also established catalytic asymmetric trans-aziridination of N-diarylmethylimines and diazoacetamides by using a boroxinate chiral Brønsted acid catalyst. 34 In addition, a couple of interesting reports discussing in detail the origin of selectivity have emerged.…”

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confidence: 71%

Development of Synthetic Transformations by Control of Acid-Catalyzed Reactions of Diazocarbonyl Compounds

Hashimoto

Maruoka

2013

Bulletin of the Chemical Society of Japan

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Diazocarbonyl compounds have long been utilized in the field of transition-metal catalysis, wherein the formation of a metalcarbene complex is involved as a key step. On the other hand, diazocarbonyl compounds can be utilized in acid catalysis owing to their intrinsic property to act as a nucleophile to an acid-activated electrophile. However, in sharp contrast to the metalcarbene chemistry, this research field has not been well developed to date as a means to synthesize complex molecular architectures. In the last several years, we have been interested in the exploration of this untapped research area to provide novel ways to synthesize a variety of complex molecules stereoselectively.

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“…In 2008, Maruoka and co-workers reported a Brønsted acid catalyzed enantioselective aziridination using N-Boc-protected imines. [33] In the context of the "Mannich" pathway as described above by Terada and coworkers, this selectivity for aziridination is remarkable. Additionally, this development is one of the few enantioselective aziridination reactions based on carbon-carbon bond formation in which the trans diastereomer is favored.…”

Section: Brønsted Acid Catalyzed Additions To Azomethinementioning

confidence: 96%

To Protonate or Alkylate? Stereoselective Brønsted Acid Catalysis of CC Bond Formation Using Diazoalkanes

2010

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A new means to activate diazoalkanes has been discovered and applied broadly over the past few years. Brønsted acids, both achiral and chiral, have been used to promote the formation of carbon-carbon and carbon-heteroatom bonds with a growing number of diazoalkane derivatives. Aside from their straightforward ability to build structural and stereochemical complexity in innovative new ways, these transformations are remarkable owing to their ability to skirt competitive diazo protonation--a reaction that has long been used to prepare esters efficiently and cleanly from carboxylic acids. In cases where achiral Brønsted acids are used, high diastereoselection can be achieved. Meanwhile, chiral Brønsted acids can deliver products with both high diastereo- and enantioselectivity. More recently, systems have emerged that combine Brønsted acids and either Lewis acids or transition metals to promote carbon-carbon bond formation from diazoalkanes.

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Trans-Selective Asymmetric Aziridination of Diazoacetamides and N-Boc Imines Catalyzed by Axially Chiral Dicarboxylic Acid

Abstract: Axially chiral dicarboxylic acid (R)-1d catalyzed reaction of diazoacetamides and N-Boc imines provided a novel organocatalytic means for the formation of enantiomerically enriched N-Boc protected trans aziridines.

Cited by 133 publications

References 34 publications

Isotope Effects and Mechanism of the Asymmetric BOROX Brønsted Acid Catalyzed Aziridination Reaction

Isotope Effects and Mechanism of the Asymmetric BOROX Brønsted Acid Catalyzed Aziridination Reaction

Development of Synthetic Transformations by Control of Acid-Catalyzed Reactions of Diazocarbonyl Compounds

To Protonate or Alkylate? Stereoselective Brønsted Acid Catalysis of CC Bond Formation Using Diazoalkanes

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