Enantioselective Synthesis of Dihydropyrazoles by Formal [4+1] Cycloaddition of in Situ-Derived Azoalkenes and Sulfur Ylides

2012 ◽  
Vol 134 (16) ◽  
pp. 6924-6927 ◽  
Author(s):  
Jia-Rong Chen ◽  
Wan-Rong Dong ◽  
Mathieu Candy ◽  
Fang-Fang Pan ◽  
Manuel Jörres ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Sulfur Ylides

ChemInform Abstract: Enantioselective Synthesis of Dihydropyrazoles by Formal [4 + 1] Cycloaddition of in situ Derived Azoalkenes and Sulfur Ylides.

ChemInform ◽  
2012 ◽  
Vol 43 (38) ◽  
pp. no-no
Author(s):  
Jia-Rong Chen ◽  
Wan-Rong Dong ◽  
Mathieu Candy ◽  
Fang-Fang Pan ◽  
Manuel Joerres ◽  
...  
Keyword(s):  
Enantioselective Synthesis ◽  
Sulfur Ylides

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 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 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.

scholarly journals Diastereoselective synthesis of CF3-dihydrobenzofurans by [4+1] annulation of in situ-generated CF3-o-quinone methides and sulfur ylides

RSC Advances ◽  
2020 ◽  
Vol 10 (63) ◽  
pp. 38588-38591
Author(s):  
Babli K. Jha ◽  
Jaggaraju Prudhviraj ◽  
Prathama S. Mainkar ◽  
Nagender Punna ◽  
Srivari Chandrasekhar
Keyword(s):  
Diastereoselective Synthesis ◽  
Quinone Methides ◽  
Reaction Conditions ◽  
Sulfur Ylides

The first [4 + 1] annulation reaction of in situ-generated highly electrophilic CF3-ortho-quinone methides with sulphur ylides has been put forth under mild reaction conditions to access CF3-dihydrobenzofurans.

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