scholarly journals Catalytic Enantioselective Synthesis of 1,4-Dihydropyridines via the Addition of C(1)-Ammonium Enolates to Pyridinium Salts

2021 ◽  
Author(s):  
Calum McLaughlin ◽  
Jacqueline Bitai ◽  
Lydia Barber ◽  
Alexandra Slawin ◽  
Andrew D Smith
Keyword(s):  
Enantioselective Synthesis ◽  
Pyridinium Salts ◽  
Stereoselective Addition

The regio- and stereoselective addition of C(1)-ammonium enolates – generated in situ from aryl esters and the isothiourea catalyst (R)-BTM – to pyridinium salts bearing an electron withdrawing substituent in...

A Short Enantioselective Synthesis of (S)-Levetiracetam Through Direct Pd-Catalyzed Asymmetric N-Allylation of Methyl 4-Aminobutyrate

Synlett ◽  
2021 ◽  
Author(s):  
Dominik Albat ◽  
Jörg-Martin Neudörfl ◽  
Hans-Günther Schmalz
Keyword(s):  
Antiepileptic Drug ◽  
Tartaric Acid ◽  
Enantioselective Synthesis

An exceedingly short and enantioselective synthesis of the antiepileptic drug (S)-levetiracetam was elaborated. As the chirogenic key step a Pd-catalyzed asymmetric N-allylation of methyl 4-aminobutyrate was achieved in the presence of only 1 mol% of a catalyst prepared in situ from [Pd(allyl)Cl]2 and the tartaric acid-derived C2-symmetric diphosphane ligand (S,S)-iPr-MediPhos).

scholarly journals One-pot synthesis of (R)-convolutamydine A involving in situ chiral organocatalyst formation

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Shengwei Wei ◽  
Bernhard Schmid ◽  
Fliur Z. Macaev ◽  
Serghei N. Curlat ◽  
Andrei V. Malkov ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
One Pot ◽  
One Pot Synthesis ◽  
Synthetic Strategy

Abstract The application of a convenient one-pot synthetic strategy, utilizing an in situ formed organocatalyst, to the enantioselective synthesis of anti-leukaemia agent (R)-convolutamydine A has been demonstrated.

scholarly journals Enantioselective Synthesis of α-(Hetero)aryl Piperidines through Asymmetric Hydrogenation of Pyridinium Salts and Its Mechanistic Insights

2018 ◽  
Vol 20 (5) ◽  
pp. 1333-1337 ◽  
Author(s):  
Bo Qu ◽  
Hari P. R. Mangunuru ◽  
Sergei Tcyrulnikov ◽  
Daniel Rivalti ◽  
Olga V. Zatolochnaya ◽  
...  
Keyword(s):  
Asymmetric Hydrogenation ◽  
Enantioselective Synthesis ◽  
Pyridinium Salts

scholarly journals Acyl Transfer Strategies as Transient Activations for Enantioselective Synthesis

Synthesis ◽  
2019 ◽  
Vol 51 (09) ◽  
pp. 1923-1934 ◽  
Author(s):  
Jean Rodriguez ◽  
Adrien Quintard
Keyword(s):  
Ring Formation ◽  
Enantioselective Synthesis ◽  
The Other ◽  
Acyl Transfer ◽  
Bifunctional Catalysis ◽  
Innovative Methods ◽  
Subsequent Step ◽  
Transfer Strategies ◽  
Amine Function

In order to circumvent reactivity or selectivity issues associated with the addition of enolates to electrophiles, chemists have devised innovative methods involving transient activating groups. One of these powerful methods consists of the use of activated ketones, such as α-nitroketones, β-dicarbonyl compounds or β-ketosulfones, with electrophiles possessing a latent hydroxy or amine function. In the presence of a suitable catalyst, an enantioselective addition to the electrophile is facilitated triggering a subsequent Claisen-type fragmentation resulting in an acyl transfer. This subsequent step unveils the desired mono-activated function while directly transferring the ketone, forming in situ on the other side an ester or an amide.1 Introduction2 Intramolecular Acyl Transfer with Acyclic Substrates2.1 Bifunctional Catalysis2.2 Aminocatalysis3 Intermolecular Acyl Transfer with Acyclic Substrates4 Medium-Sized-Ring Formation with Cyclic Substrates5 Conclusion

Intramolecular Michael Addition of N- and O-Centred Nucleophiles to Tethered Acrylates. The Role of Double-Bond Geometry in Controlling the Diastereo- selectivity of Cyclizations Leading to 2,6-Disubstituted Tetrahydropyrans and Piperidines.

1998 ◽  
Vol 51 (1) ◽  
pp. 9 ◽  
Author(s):  
Martin G. Banwell ◽  
Brett D. Bissett ◽  
Chinh T. Bui ◽  
Ha T. T. Pham ◽  
Gregory W. Simpson
Keyword(s):  
Double Bond ◽  
Total Synthesis ◽  
Michael Addition ◽  
Reductive Amination ◽  
Major Product ◽  
Enantioselective Synthesis ◽  
Cyclization Reactions ◽  
Glandular Secretion

The oxyanion derived from hydroxyacrylate E-(5) undergoes smooth intramolecular Michael addition to give the trans-2,6-disubstituted tetrahydropyran (7) as the major product of reaction. In contrast, the oxyanion obtained from isomer Z-(5) cyclizes to give the cis-2,6-disubstituted tetrahydropyran (6) as the major product. Such chemistry has been extended to the enantioselective synthesis of (+)-(6) the acquisition of which constitutes a formal total synthesis of acid (+)-(2), a constituent of the glandular secretion from the civet cat (Viverra civetta). Reductive amination of keto acrylate (12) affords an intermediate amine which cyclizes, in situ, to give the cis-2,6-disubstituted piperidine (26). Analogous treatment of compound (13) delivers the isomeric trans-2,6-disubstituted piperidine (27) as the exclusive product of reaction. Transition state structures have been proposed to account for the diastereoselectivities observed in all of the cyclization reactions.

Enantioselective Synthesis of Dihydropyridines Containing Quaternary Stereocenters Through Dearomatization of Pyridinium Salts

ACS Catalysis ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 51-55 ◽  
Author(s):  
Donovan J. Robinson ◽  
Sean P. Spurlin ◽  
John D. Gorden ◽  
Rashad R. Karimov
Keyword(s):  
Enantioselective Synthesis ◽  
Pyridinium Salts ◽  
Quaternary Stereocenters

Enantioselective synthesis of chiral α-alkynylated thiazolidones by tandem S-addition/acetalization of alkynyl imines

2020 ◽  
Vol 18 (16) ◽  
pp. 3117-3124
Author(s):  
Mei-Xin Wang ◽  
Juan Liu ◽  
Zhen Liu ◽  
Yingcheng Wang ◽  
Qi-Qiong Yang ◽  
...  
Keyword(s):  
Enantioselective Synthesis

A SPINOL-CPA catalyzed asymmetric [2 + 3]-annulation of in situ generated alkynyl imines and 1,4-dithiane-2,5-diol has been developed to afford enantiopure α-alkynylated thiazolidones.

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