scholarly journals Applications of "planar-chiral" heterocycles in asymmetric catalysis

2001 ◽  
Vol 73 (7) ◽  
pp. 1113-1116 ◽  
Author(s):  
Gregory C. Fu
Keyword(s):  
Asymmetric Catalysis ◽  
Ring Opening ◽  
Kinetic Resolution ◽  
Ring Expansion ◽  
Chiral Ligands ◽  
Primary Amines ◽  
Allylic Alcohols ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Derivatives Of

Planar-chiral derivatives of pyridine function as efficient catalysts for processes such as the kinetic resolution of primary amines and the desymmetrization/ring-opening of meso epoxides. Planar-chiral pyrrolyl and phospholyl derivatives serve as effective chiral ligands for a range of metal-catalyzed reactions, including the copper-catalyzed ring-expansion of oxetanes and the rhodium-catalyzed isomerization of allylic alcohols.

scholarly journals Recent Advances in the Synthesis of Hydrogenated Azocine-Containing­ Molecules

Synthesis ◽  
2017 ◽  
Vol 49 (17) ◽  
pp. 3801-3834 ◽  
Author(s):  
Anna Listratova ◽  
Leonid Voskressensky
Keyword(s):  
Ring Opening ◽  
Aldol Condensation ◽  
Ring Expansion ◽  
Radical Cyclization ◽  
Primary Amines ◽  
Ring Closing Metathesis ◽  
Recent Advances ◽  
Activated Alkynes ◽  
Ring Expansion Reaction ◽  
Metal Catalyzed

This review covers recent advances in synthesis of azocine-containing systems. The most approaches towards azocines are discussed.1 Introduction2 Ring-Expansion Reaction2.1 Ring-Expansion Reaction of Cyclopentane Containing the 1,4-Diketone Moiety with Primary Amines (from 5 to 8)2.2 Ring-Expansion Reaction of Annulated Tetrahydropyridines under the Action of Activated Alkynes (from 6 to 8)2.3 Reductive Ring-Expansion Reaction of Cyclic Oximes2.4 Other Ring-Expansion Reactions3 Heck Reaction4 Cycloaddition5 Ring-Closing Metathesis (RCM)6 Cyclization6.1 Metal-Catalyzed Cyclization6.2 Radical Cyclization6.3 Friedel–Crafts Cyclization6.4 Other Examples of Cyclizations7 Microwave- and Photo-Assisted Reactions8 Other Methods8.1 Cascade and Tandem Reactions8.2 Aldol Condensation8.3 Thermolysis8.4 Ring Opening8.5 Other Methods9 Conclusion

(–)-Sparteine-mediated stereoselective directed ortho metalation of ferrocene diamides

2006 ◽  
Vol 84 (2) ◽  
pp. 356-369 ◽  
Author(s):  
Radoslaw Laufer ◽  
Ulrich Veith ◽  
Nicholas J Taylor ◽  
Victor Snieckus
Keyword(s):  
Asymmetric Catalysis ◽  
Chiral Ligands ◽  
Asymmetric Alkylation ◽  
Allylic Substitutions ◽  
Ortho Metalation ◽  
Palladium Catalyzed ◽  
Derivatives Of

The utility of (–)-sparteine-mediated directed ortho metalation (DoM) has been investigated in stereoselective preparation of planar chiral ferrocenes derived from 1,1′-N,N,N′,N′-tetraisopropylferrocenedicarboxamide (5). In the synthesis of C2-symmetric analogs of 5, the protocol (base, solvent, and two-step DoM) was found to be crucial for obtaining high enantio- and diastereo-selectivities of the products. A variety of highly enantioenriched mono and doubly functionalized derivatives of 5 have been synthesized. The synthetic applications of these compounds as chiral ligands in asymmetric alkylation of aldehydes and asymmetric palladium-catalyzed allylic substitutions have been demonstrated.Key words: directed ortho metalation, stereoselective deprotonation, ferrocene ligands, asymmetric catalysis.

scholarly journals Progress on the Stereoselective Synthesis of Chiral Molecules Based on Metal-Catalyzed Dynamic Kinetic Resolution of Alcohols with Lipases

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1744
Author(s):  
Raffaella Ferraccioli
Keyword(s):  
Kinetic Resolution ◽  
Stereoselective Synthesis ◽  
Cascade Reactions ◽  
Allylic Alcohols ◽  
Chiral Molecules ◽  
Dynamic Kinetic Resolution ◽  
Multiple Bonds ◽  
One Pot ◽  
Synthetic Utility ◽  
Metal Catalyzed

Metal/lipase-combo catalyzed dynamic kinetic resolution (DKR) of racemic chiral alcohols is a general and practical process to obtain the corresponding enantiopure esters R with quantitative conversion. The use of known Ru-catalysts as well as newly developed homogeneous and heterogeneous metal catalysts (Fe, V) contributed to make the DKR process more sustainable and to expand the substrate scope of the reaction. In addition to classical substrates, challenging allylic alcohols, tertiary alcohols, C1-and C2-symmetric biaryl diols turned out to be competent substrates. Synthetic utility further emerged from the integration of this methodology into cascade reactions leading to linear/cyclic chiral molecules with high ee through the formation of multiple bonds, in a one-pot procedure.

Fluorous derivatives of (1R,2R)-diaminocyclohexane as chiral ligands for metal-catalyzed asymmetric reactions

2005 ◽  
Vol 16 (13) ◽  
pp. 2319-2327 ◽  
Author(s):  
Jerome Bayardon ◽  
Denis Sinou ◽  
Orsolya Holczknecht ◽  
Lászlo Mercs ◽  
Gianluca Pozzi
Keyword(s):  
Asymmetric Reactions ◽  
Chiral Ligands ◽  
Metal Catalyzed ◽  
Derivatives Of

scholarly journals Stereoselective Synthesis and Investigation of Isopulegol-Based Chiral Ligands

2019 ◽  
Vol 20 (16) ◽  
pp. 4050 ◽  
Author(s):  
Tam Minh Le ◽  
Tamás Szilasi ◽  
Bettina Volford ◽  
András Szekeres ◽  
Ferenc Fülöp ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Ring Opening ◽  
Stereoselective Synthesis ◽  
Substituent Effects ◽  
Ring Closure ◽  
Chiral Ligands ◽  
Primary Amines ◽  
Structure Activity ◽  
Stereoselective Reactions ◽  
Stereoselective Epoxidation

A library of isopulegol-based bi-, tri- and tetrafunctional chiral ligands has been developed from commercially available (−)-isopulegol and applied as chiral catalysts in the addition of diethylzinc to benzaldehyde. Michael addition of primary amines towards α-methylene-γ-butyrolactone, followed by reduction, was accomplished to provide aminodiols in highly stereoselective transformations. Stereoselective epoxidation of (+)-neoisopulegol, derived from natural (−)-isopulegol, and subsequent oxirane ring opening with primary amines afforded aminodiols. The regioselective ring closure of N-substituted aminodiols with formaldehyde was also investigated. Hydroxylation of (+)-neoisopulegol resulted in diol, which was then transformed into aminotriols by aminolysis of its epoxides. Dihydroxylation of (+)-neoisopulegol or derivatives with OsO4/NMO gave neoisopulegol-based di-, tri- and tetraols in highly stereoselective reactions. The antimicrobial activity of aminodiol and aminotriol derivatives as well as di-, tri- and tetraols was also explored. In addition, structure–activity relationships were examined by assessing substituent effects on the aminodiol and aminotriol systems.

scholarly journals Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

2019 ◽  
Vol 15 ◽  
pp. 679-684 ◽  
Author(s):  
Vaida Milišiūnaitė ◽  
Rūta Paulavičiūtė ◽  
Eglė Arbačiauskienė ◽  
Vytas Martynaitis ◽  
Wolfgang Holzer ◽  
...  
Keyword(s):  
Pyrazole Ring ◽  
Ring System ◽  
Ring Closure ◽  
X Ray Diffraction ◽  
Efficient Procedure ◽  
Ring Systems ◽  
X Ray ◽  
Catalyzed Reactions ◽  
Metal Catalyzed ◽  
Derivatives Of

Fused pyrazole ring systems are common structural motifs of numerous pharmaceutically important compounds. Nevertheless, access to derivatives of the aromatic 2H-furo[2,3-c]pyrazole ring system is still quite limited, and their chemistry and functional properties remain largely underexplored. The current study investigates routes to construct this system from easily accessible starting materials using metal-catalyzed reactions. A simple and efficient procedure to access the 2H-furo[2,3-c]pyrazole ring system was developed by employing the silver(I) ion-mediated ring-closure reaction of 4-alkynyl-3-hydroxy-1-phenyl-1H-pyrazoles as a key step. The required intermediate hydroxyalkynyl substrates for this reaction were prepared by a Pd-catalyzed coupling of 4-iodo-1-phenyl-1H-pyrazol-3-ol with ethyne derivatives. The structures of the obtained target compounds were unequivocally confirmed by detailed 1H, 13C and 15N NMR spectroscopic experiments, HRMS and a single-crystal X-ray diffraction analyses. This silver(I)-mediated 5-endo-dig cyclization of readily available 4-alkynyl-3-hydroxy-1H-pyrazoles can be used as an efficient method to access many novel 2,5-disubstituted 2H-furo[2,3-c]pyrazoles.

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