Decarboxylative Organocatalytic Allylic Amination of Morita–Baylis–Hillman Carbamates

Dočekal, Vojtěch; Šimek, M.; Dračínský, Martin; Veselý, Ján

doi:10.1002/chem.201803677

Cited by 16 publications

(6 citation statements)

References 75 publications

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“…Lastly, the activity of all prepared CD derivatives was tested in asymmetric organocatalytic reactions. After unsuccessful application in Morita–Baylis–Hillman and aldol-type reactions, we focused on their application in the decarboxylative asymmetric allylic amination (AAA) [38] of MBH carbamate 12 affording the product 13 with enantiomeric excesses of up to 75% (Scheme 4).…”

Section: Resultsmentioning

confidence: 99%

“…However, compared with the published procedure [38] (up to 97% ee, aromatic solvent, 40 °C, and 168 hours), the solvent of the reaction had to be changed in the case of non-methylated CDs due to their lower solubility in organic solvents. The reaction conditions and results are summed up in Table 3.…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, the non-methylated monosubstituted CD derivatives 4a–d , 5a–d afforded on one side lower enantiomer excesses (Table 3, entries 18 – 28), on the other hand, they showed some catalytic activity in the solvent mixture acetonitrile/H 2 O, which could be promising for future applications of these catalysts in water. The disubstituted CD derivative 11 was not active in this enantioselective reaction (Table 3, entry 29) and this derivative was also tested in the AAA reaction with (1 S )-10-camphorsulfonic acid (CSA) according to the original procedure [38], in which the cocatalyst (1 S )-CSA enhanced the efficiency of dimeric cinchona alkaloids (Table 3, entry 30). However, there was no difference observable under these conditions.…”

Section: Resultsmentioning

confidence: 99%

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New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

Tichá

Hybelbauerová

Jindřich

2019

Beilstein J. Org. Chem.

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The preparation of new organocatalysts for asymmetric syntheses has become a key stage of enantioselective catalysis. In particular, the development of new cyclodextrin (CD)-based organocatalysts allowed to perform enantioselective reactions in water and to recycle catalysts. However, only a limited number of organocatalytic moieties and functional groups have been attached to CD scaffolds so far. Cinchona alkaloids are commonly used to catalyze a wide range of enantioselective reactions. Thus, in this study, we report the preparation of new α- and β-CD derivatives monosubstituted with cinchona alkaloids (cinchonine, cinchonidine, quinine and quinidine) on the primary rim through a CuAAC click reaction. Subsequently, permethylated analogs of these cinchona alkaloid–CD derivatives also were synthesized and the catalytic activity of all derivatives was evaluated in several enantioselective reactions, specifically in the asymmetric allylic amination (AAA), which showed a promising enantiomeric excess of up to 75% ee. Furthermore, a new disubstituted α-CD catalyst was prepared as a pure AD regioisomer and also tested in the AAA. Our results indicate that (i) the cinchona alkaloid moiety can be successfully attached to CD scaffolds through a CuAAC reaction, (ii) the permethylated cinchona alkaloid–CD catalysts showed better results than the non-methylated CDs analogues in the AAA reaction, (iii) promising enantiomeric excesses are achieved, and (iv) the disubstituted CD derivatives performed similarly to monosubstituted CDs. Therefore, these new CD derivatives with cinchona alkaloids effectively catalyze asymmetric allylic aminations and have the potential to be successfully applied in other enantioselective reactions.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

Tichá

Hybelbauerová

Jindřich

2019

Beilstein J. Org. Chem.

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“…This strategy has been extensively exploited using a myriad of stabilised or acidic pronucleophiles, which upon in situ deprotonation by the ionised leaving group enables the stereoselective formation of new C-C, 4 C-N, C-O, 6 C-S, 7 and C-P 8 allylic bonds in product 3 (Scheme 1B, path i). Recently, MBH adducts bearing alternative leaving groups to acetates and carbonates, including fluorides 9 and carbamates, 10 have been successfully implemented in allylic substitutions under chiral Lewis base (LB) catalysis, allowing the asymmetric installation of amino, 9c,10 trifluoromethyl, 9a and alkynyl 9b groups with excellent regio-and enantiocontrol.…”

Section: Introductionmentioning

confidence: 99%

Unconventional Transformations of Morita–Baylis–Hillman Adducts

Calcatelli

Cherubini‐Celli²,

Carletti³

et al. 2020

Synthesis

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Morita–Baylis–Hillman (MBH) adducts are versatile starting materials widely employed in Lewis base catalysis. A myriad of different transformations have been reported based on either allylic alkylations with stabilised nucleophiles or annulations with diverse dipolarophiles. Apart from these two conventional types of reactivity, MBH adducts have recently been implemented in alternative and complementary catalytic strategies, including: (i) one-pot and cascade transformations, where additional chemical bonds are formed following the asymmetric allylic alkylation event in a single synthetic operation; (ii) regioselective α-allylations for the synthesis of trisubstituted alkenes; and (iii) dual activation strategies, involving Lewis base catalysis together with transition metal complexes or light, enabling allylic alkylations with nonstabilised nucleophiles and cascade processes. The present Short Review summarises the most significant unconventional catalytic transformations of racemic MBH adducts reported within the last decade.1 Introduction2 Multi-Step Single-Vessel Transformations (path iii)2.1 One-Pot Transformations2.2 Cascade Transformations3 α-Allylations (path iv)3.1 SN2′ Mechanism3.2 SN2′–SN2 Mechanism3.3 Miscellaneous Mechanisms4 Dual Activation (path v)4.1 MBH Adduct as Electrophile4.2 MBH Adduct as Nucleophile5 Summary and Outlook

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“…Despite the significant utility, all of the above transformations are based on the utilization of 1,2-difunctional benzenes, such as anthranilamides, 2-haloanilines, anthranilic esters, 2-haloisocyanatobenzenes, and 2-aminoarylmethanols. The key issue is that the preparation of these reactants generally requires multiple prefunctionalization steps . As a result, the application of these protocols toward synthetic diversity is easily restricted.…”

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confidence: 99%

Copper-Catalyzed Oxidative Multicomponent Annulation Reaction for Direct Synthesis of Quinazolinones via an Imine-Protection Strategy

et al. 2019

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Via an imine-protection strategy, we herein present an unprecedented copper-catalyzed oxidative multicomponent annulation reaction for direct synthesis of quinazolinones. The construction of various products is achieved via formation of three C−N and one C− C bonds in conjunction with the benzylic functionalization. The merits of easily available feedstocks, naturally abundant catalyst, good functional group and substrate compatibility, and release of H 2 O as the byproduct make the developed chemistry a practical way to access quinazolinones.

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Decarboxylative Organocatalytic Allylic Amination of Morita–Baylis–Hillman Carbamates

Cited by 16 publications

References 75 publications

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

New α- and β-cyclodextrin derivatives with cinchona alkaloids used in asymmetric organocatalytic reactions

Unconventional Transformations of Morita–Baylis–Hillman Adducts

Copper-Catalyzed Oxidative Multicomponent Annulation Reaction for Direct Synthesis of Quinazolinones via an Imine-Protection Strategy

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