scholarly journals Lithium Enolates Derived from Weinreb Amides: Insights into Five-Membered Chelate Rings

2016 ◽  
Vol 81 (22) ◽  
pp. 11057-11064 ◽  
Author(s):  
Michael J. Houghton ◽  
David B. Collum
2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Mircea Braban ◽  
Ionel Haiduc

The paper describes the solid state structure of a compound of composition [Cu(bipy)3][Cu(bipy)(ala) (ClO4)2]ClO4, in which both the cation and anion are octahedral complex species with copper(II) as coordination center. The cation contains three chelate rings formed by bipy; the anion contains in the quatorial plane a CuONC2 chelate ring formed by the alaninato ligand and a CuN2C2 chelate ring formed by bipy, with two monodentate perchorato ligands in axial positions completing the six-coordination. In the crystal p-p stackings lead to a supramolecular self-assembled structure.


2019 ◽  
Vol 23 (19) ◽  
pp. 2102-2121
Author(s):  
Hiroyuki Kawafuchi ◽  
Lijian Ma ◽  
Md Imran Hossain ◽  
Tsutomu Inokuchi

O-Acylated 2,2,6,6-tetramethylpiperidine-N-oxyls (abbr. O-AcylTEMPOs) are easily available and stable carboxylic derivatives, but their utility in organic synthesis is unexplored in contrast to analogues, such as the N-methoxy-N-methylamides, known as Weinreb amides. Especially, the O–N unit of the O-acylTEMPOs dictates a fairly electronwithdrawing character for the carbonyl function. This enhances the reactivity and stability of the resulting enolate ions. Accordingly, O-acylTEMPOs allow various transformations and this review encompasses seven topics: (1) Reactivity of O-acylTEMPOs towards nucleophiles and chemoselective transformations, (2) Reactivity of anionic species derived from O-acylTEMPOs, (3) E-Selective Knoevenagel condensation of acetoacetylTEMPOs and synthesis of furans, (4) Electrocyclization of 2,4-dienones derived from acetoacetic derivatives and 2-substituted enals, (5) Diastereoselective addition of amide anion to O-(2-alkenoyl)TEMPOs and β-amino acid synthesis, (6) Thermolysis of O-acylTEMPOs, and (7) Applications for Umpolung reactions using O-benzoylTEMPOs, useful for the electrophilic amination of alkenes and alkynes.


2007 ◽  
Vol 72 (25) ◽  
pp. 9850-9853 ◽  
Author(s):  
Hisao Nemoto ◽  
Rujian Ma ◽  
Hideki Moriguchi ◽  
Tomoyuki Kawamura ◽  
Masaki Kamiya ◽  
...  

ChemInform ◽  
2016 ◽  
Vol 47 (43) ◽  
Author(s):  
Soda Chanthamath ◽  
Hamada S. A. Mandour ◽  
Thu Minh Thi Tong ◽  
Kazutaka Shibatomi ◽  
Seiji Iwasa
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