Enantioselective intramolecular cyclization of alkynyl esters catalyzed by a chiral Brønsted base

2016 ◽  
Vol 52 (33) ◽  
pp. 5726-5729 ◽  
Author(s):  
Azusa Kondoh ◽  
Hoa Thi Quynh Tran ◽  
Kyoko Kimura ◽  
Masahiro Terada
Keyword(s):  
Schiff Base ◽  
Intramolecular Cyclization ◽  
Cyclization Reaction ◽  
Base Catalyst ◽  
Chiral Schiff Base ◽  
Brønsted Base

An enantioselective intramolecular cyclization reaction of alkynyl esters was developed, which employs a Brønsted base catalyst generated in situ from a chiral Schiff base and t-BuOK.

scholarly journals Structural Characterization of Heterodinuclear ZnII-LnIII Complexes (Ln = Pr, Nd) with a Ring-Contracted H2valdien-Derived Schiff Base Ligand

2021 ◽  
Author(s):  
Shabana Noor ◽  
Richard Goddard ◽  
Fehmeeda Khatoon ◽  
Sarvendra Kumar ◽  
Rüdiger W. Seidel
Keyword(s):  
Molecular Structure ◽  
Schiff Base ◽  
Structural Characterization ◽  
Schiff Base Ligand ◽  
Crystal And Molecular Structure ◽  
X Ray ◽  
X Ray Crystallography ◽  
Imidazoline Ring

AbstractSynthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes with the formula [ZnLn(HL)(µ-OAc)(NO3)2(H2O)x(MeOH)1-x]NO3 · n H2O · n MeOH [Ln = Pr (1), Nd (2)] and the crystal and molecular structure of [ZnNd(HL)(µ-OAc)(NO3)2(H2O)] [ZnNd(HL)(OAc)(NO3)2(H2O)](NO3)2 · n H2O · n MeOH (3) are reported. The asymmetrical compartmental ligand (E)-2-(1-(2-((2-hydroxy-3-methoxybenzylidene)amino)-ethyl)imidazolidin-2-yl)-6-methoxyphenol (H2L) is formed from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation, resulting in a peripheral imidazoline ring. The structures of 1–3 were revealed by X-ray crystallography. The smaller ZnII ion occupies the inner N2O2 compartment of the ligand, whereas the larger and more oxophilic LnIII ions are found in the outer O2O2’ site. Graphic Abstract Synthesis and structural characterization of two heterodinuclear ZnII-LnIII complexes (Ln = Pr, Nd) bearing an asymmetrical compartmental ligand formed in situ from N1,N3-bis(3-methoxysalicylidene)diethylenetriamine (H2valdien) through intramolecular aminal formation are reported.

Syntheses, Spectroscopy And Crystal Structures Of (R)-N-(1-Aryl-Ethyl)Salicylaldimines And [Rh{(R)-N-(1-Aryl-Ethyl)Salicylaldiminato}(η4-Cod)] Complexes

2007 ◽  
Vol 62 (6) ◽  
pp. 807-817 ◽  
Author(s):  
Mohammed Enamullah ◽  
A.K.M. Royhan Uddin ◽  
Anne-Christine Chamayou ◽  
Christoph Janiak
Keyword(s):  
Mass Spectrometry ◽  
Schiff Base ◽  
Schiff Bases ◽  
Structure Determination ◽  
Chelate Ring ◽  
Optical Rotation ◽  
X Ray ◽  
Mononuclear Complexes ◽  
Chiral Schiff Base ◽  
C Nmr

Condensation of salicylaldehyde with enantiopure (R)-(1-aryl-ethyl)amines yields the enantiopure Schiff bases (R)-N-(1-aryl-ethyl)salicylaldimine (HSB*; aryl = phenyl, 2-methoxyphenyl, 3- methoxyphenyl, 4-methoxyphenyl (4), 4-bromophenyl (5), 2-naphthyl). These Schiff bases readily react with dinuclear (acetato)(η4-cycloocta-1,5-diene)rhodium(I), [Rh(μ-O2CMe)(η4-cod)]2, to afford the mononuclear complexes, cyclooctadiene-((R)-N-(1-aryl-ethyl)salicylaldiminato-κ2N,O)- rhodium(I), [Rh(SB∗)(η4-cod)] (SB* = deprotonated chiral Schiff base = salicylaldiminate; aryl = phenyl (7), 2-methoxyphenyl, 4-methoxyphenyl, 4-bromophenyl, 2-naphthyl). The complexes have been characterized by IR, UV/vis, 1H/13C NMR and mass spectrometry, optical rotation as well as by single-crystal X-ray structure determination for 4, 5 and 7. The structure of 5 shows C-Br· · ·π contacts. Compound 7 is only the second example of a Rh(η4-cod) complex with a six-membered Rh-N,O-chelate ring

ChemInform Abstract: Efficient Synthesis of 2,8-Diazabicyclo(4.3.0)nonane Derivatives via Intramolecular Cyclization Reaction.

ChemInform ◽  
2010 ◽  
Vol 27 (7) ◽  
pp. no-no
Author(s):  
J. W. LEE ◽  
H. J. SON ◽  
J. H. LEE ◽  
Y. E. JUNG ◽  
G. J. YOON ◽  
...  
Keyword(s):  
Intramolecular Cyclization ◽  
Cyclization Reaction ◽  
Efficient Synthesis

scholarly journals Fabrication of injectable hydrogels based on poly(l-glutamic acid) and chitosan

RSC Advances ◽  
2017 ◽  
Vol 7 (28) ◽  
pp. 17005-17019 ◽  
Author(s):  
Shifeng Yan ◽  
Taotao Wang ◽  
Xing Li ◽  
Yuhang Jian ◽  
Kunxi Zhang ◽  
...  
Keyword(s):  
Schiff Base ◽  
Glutamic Acid ◽  
Crosslinking Reaction ◽  
Injectable Hydrogels ◽  
Oppositely Charged

The in situ forming hydrogels based on oppositely charged poly(l-glutamic acid) (PLGA) and chitosan (CS) were prepared via a Schiff base crosslinking reaction.

Dinuclear zinc-catalyzed asymmetric [3+2] cyclization reaction for direct assembly of chiral α-amino-γ-butyrolactones bearing three stereocenters

2021 ◽  
Author(s):  
Wen-Peng Yang ◽  
Shi-Kun Jia ◽  
Tian-Tian Liu ◽  
Yuan-Zhao Hua ◽  
Mincan Wang
Keyword(s):  
Lewis Acid ◽  
Cyclization Reaction ◽  
Activation Model ◽  
Direct Assembly ◽  
Brønsted Base ◽  
Cooperative Activation

An efficient enantioselective [3+2] cyclization reaction of α-hydroxy-1-indanones and alkylidene azlactones has been developed with chiral dinuclear zinc catalysts via a Brønsted base and Lewis acid cooperative activation model. This...

Mix and match: templating chiral Schiff base ligands to suit the needs of the metal ion

2010 ◽  
Vol 39 (22) ◽  
pp. 5332 ◽  
Author(s):  
Edwin C. Constable ◽  
Guoqi Zhang ◽  
Catherine E. Housecroft ◽  
Jennifer A. Zampese
Keyword(s):  
Schiff Base ◽  
Metal Ion ◽  
Schiff Base Ligands ◽  
Chiral Schiff Base ◽  
Mix And Match

Molybdenum(vi) cis-dioxo complexes bearing sugar derived chiral Schiff-base ligands: synthesis, characterization, and catalytic applications

2003 ◽  
pp. 3736-3742 ◽  
Author(s):  
Jin Zhao ◽  
Xiangge Zhou ◽  
Ana M. Santos ◽  
Eberhardt Herdtweck ◽  
Carlos C. Romão ◽  
...  
Keyword(s):  
Schiff Base ◽  
Schiff Base Ligands ◽  
Chiral Schiff Base ◽  
Catalytic Applications
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