Proline‐Related Secondary Amine Catalysts and Applications

Kotsuki, Hiyoshizo; Sasakura, Niiha

doi:10.1002/9783527658862.ch1

Cited by 7 publications

(4 citation statements)

References 370 publications

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“…Secondary amines are versatile nitrogenated compounds with multiple applications in organic chemistry as, for example, organocatalysts, Lewis bases (e.g., for the activation of electron-deficient olefins), or building scaffolds for multicomponent reactions, among many others. On the other hand, in organic chemistry, it is desirable that the selective conversion of a single starting material into two or more different products can be accomplished by the selection of the catalyst .…”

Section: Resultsmentioning

confidence: 99%

Synthesis of Aminoindolizidines through the Chemoselective and Diastereoselective Catalytic Hydrogenation of Indolizines

2016

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Indolizidines are great-potential bioactive heterocyclic compounds normally prepared following multi-step routes. However, to the best of our knowledge, the synthesis of 1-amino indolizidines has never been reported. Herein, 1-dialkylamino-3-substituted indolizidines have been straightforwardly synthesized using an atom-economy protocol which involves a copper-catalyzed three-component synthesis of indolizines followed by heterogeneous catalytic hydrogenation. The latter was found to be chemoselective using platinum(IV) oxide as the catalyst at 3.7 atm, providing the amino indolizidines in modest-to-high yields (35-95%) and high diastereoselectivity (92:8 to > 99:1).It has been experimentally demonstrated that the hydrogenation occurs through the intermediate 5,6,7,8-tetrahydroindolizine, which contains a pyrrole moiety. Moreover, the diastereomerically pure 1-dibenzylamino-3-substituted indolizidines could be further transformed into the corresponding monobenzylated or fully debenzylated amino indolizidines by selective hydrogenolysis catalyzed by Pt/C or Pd/C, respectively, under ambient conditions.

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Section: Resultsmentioning

confidence: 99%

Synthesis of Aminoindolizidines through the Chemoselective and Diastereoselective Catalytic Hydrogenation of Indolizines

2016

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“…After protection of a phenolic hydroxyl group of 6 with a photo‐removable o NB group, the obtained product was successfully employed for further transformation to generate Fmoc‐protected UV‐responsive Spr 3 . Whereas racemic 3 was prepared in the first preparation of UV‐responsive Spr, enantioselective synthesis of ( S )‐ 3 was achieved later by the use of a proline‐based tetrazole catalyst (Scheme ) . We have yet to examine whether chirality of Spr affects activity and/or conformation of peptides/proteins possessing Spr; therefore, it should be addressed in due course.…”

Section: Chemistry Of the Sprmentioning

confidence: 99%

Invention of stimulus‐responsive peptide‐bond‐cleaving residue (Spr) and its application to chemical biology tools

Shigenaga

Yamamoto

Kohiki

et al. 2017

Journal of Peptide Science

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Elucidation of biological functions of peptides and proteins is essential for understanding peptide/protein-related biological events and developing drugs. Caged peptides and proteins that release a parent active peptide/protein by photo-irradiation have successfully been employed to elucidate the functions. Whereas the usual caged peptide/protein enables conversion of an inactive form to an active form (OFF-to-ON conversion) by photo-induced deprotection, photo-triggered main chain cleavage is reported to be applicable to ON-to-OFF conversion. These peptides and proteins are photo-responsive; however, if peptides and proteins could respond to other stimuli such as disease-related environment or enzymes, their range of application should be widened. To convert the photo-responsive peptide/protein into other stimulus-responsive peptide/protein, quite laborious de novo design and synthesis of the stimulus-responsive unit are required. In this context, we designed a stimulus-responsive peptide-bond-cleaving residue (Spr) in which the stimuli available for the main chain cleavage vary according to the choice of protecting groups on the residue. In this review, design and synthesis of Spr are introduced, and challenges to apply Spr to other fields to enable, for example, functional control, localization control, delivery of cargos, labeling of a protein of interest in living cells, and identification of target proteins of bioactive ligands are discussed. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.

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“…Thus, we considered intriguing to develop novel binaphthylazepinebased organocatalysts in which the atropisomeric chirality of the binaphthyl moiety was joined to a central chirality element close to the amino group and bearing the required acidic function. In fact, this is the common structural feature of proline (2a) and prolinederived amino acids, amino alcohols, and amino ethers, which have been widely utilized in many organocatalytic reactions and are often considered the benchmark to compare the efficiency of new catalysts [23][24][25]. Nevertheless, the low solubility of proline (2a) in certain organic solvents and the slow turnover rates sometimes displayed have led to the discovery of other related catalytic systems that overcome some of these drawbacks, such as 5-pyrrolidin-2-yl-1H-tetrazole (2b).…”

Section: Introductionmentioning

confidence: 99%

Synthesis and Stereochemical Characterization of a Novel Chiral α-Tetrazole Binaphthylazepine Organocatalyst

et al. 2022

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A novel α-tetrazole-substituted 1,1′-binaphthylazepine chiral catalyst has been synthesized and its absolute configuration has been determined by DFT computational analysis of the vibrational circular dichroism (VCD) spectrum of its precursor. The VCD analysis, carried out through the model averaging method, allowed to assign the absolute configuration of a benzylic stereocenter in the presence of a chiral binaphthyl moiety. The 1,1′-binaphthylazepine tetrazole and the nitrile its immediate synthetic precursor, have been preliminarily tested as chiral organocatalysts in the asymmetric intramolecular oxa-Michael cyclization of 2-hydroxy chalcones for the synthesis of chiral flavanones obtaining low enantioselectivity.

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Proline‐Related Secondary Amine Catalysts and Applications

Cited by 7 publications

References 370 publications

Synthesis of Aminoindolizidines through the Chemoselective and Diastereoselective Catalytic Hydrogenation of Indolizines

Synthesis of Aminoindolizidines through the Chemoselective and Diastereoselective Catalytic Hydrogenation of Indolizines

Invention of stimulus‐responsive peptide‐bond‐cleaving residue (Spr) and its application to chemical biology tools

Synthesis and Stereochemical Characterization of a Novel Chiral α-Tetrazole Binaphthylazepine Organocatalyst

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