ChemInform Abstract: ENANTIOSELECTIVE 1,2-ADDITIONS OF ORGANOLITHIUM, -MAGNESIUM, -ZINC, AND -COPPER COMPOUNDS AND LITHIUM ENOLATES TO CARBONYL COMPOUNDS IN A CHIRAL 1,4-BIS(DIMETHYLAMINO)-2,3-DIMETHOXYBUTANE MEDIUM

1979 ◽  
Vol 10 (52) ◽  
Author(s):  
D. SEEBACH ◽  
W. LANGER
Keyword(s):  
Carbonyl Compounds ◽  
Copper Compounds ◽  
Lithium Enolates

A computational study of the 1,4-addition of lithium enolates to conjugated carbonyl compounds

1992 ◽  
Vol 57 (26) ◽  
pp. 7029-7034 ◽  
Author(s):  
Anna Bernardi ◽  
Anna Maria Capelli ◽  
Andrea Cassinari ◽  
Angiolina Comotti ◽  
Cesare Gennari ◽  
...  
Keyword(s):  
Carbonyl Compounds ◽  
Computational Study ◽  
Lithium Enolates

Aminolithiation of carbon-carbon double bonds as a powerful tool in organic synthesis

2009 ◽  
Vol 81 (2) ◽  
pp. 247-253 ◽  
Author(s):  
Kiyoshi Tomioka ◽  
Takeo Sakai ◽  
Tokutaro Ogata ◽  
Yasutomo Yamamoto
Keyword(s):  
Carbonyl Compounds ◽  
Chiral Ligand ◽  
Powerful Method ◽  
Double Bonds ◽  
One Pot ◽  
Bond Forming ◽  
Lithium Amides ◽  
Lithium Enolates ◽  
Amination Product

A conjugate amination of α,β-unsaturated carbonyl compounds with lithium amides has become a powerful method of N-C bond-forming reactions. Chiral ligand-controlled asymmetric version of the conjugate amination of enoates was developed for practical bench chemistry, giving the enantioenriched amination product with over 99 % ee. In situ diastereoselective alkylation of resulting lithium enolates allowed us to form vicinal N-C and C-C bonds in a one-pot operation. This protocol enabled us to realize a short-step asymmetric synthesis of otamixaban key intermediate. Treatment of product 3-benzylamino- and 3-allylaminoesters with tert-butyllithium gave five- or seven-membered lactams through [1,2]- or [2,3]-rearrangement of intermediate β-lactams. Isolated C-C double bonds were also found to accept intramolecular aminolithiation affording the corresponding hydroamination products. Chiral lithiophilic ligand-catalyzed reaction gave enantioenriched hydroamination products with high ee. Stereoselective intramolecular aminolithiation of allylaminoalkenes was coupled with subsequent carbolithiation to give doubly cyclized product amines.

The α-alkoxycarbonylation of saturated carbonyl compounds. The synthesis of 17α-hydroxymethyl 20-keto steroids

1978 ◽  
Vol 56 (3) ◽  
pp. 410-418 ◽  
Author(s):  
D. Mukherjee ◽  
CH. R. Engel
Keyword(s):  
Free Radical ◽  
Carbonyl Compounds ◽  
Keto Group ◽  
Methyl Group ◽  
Lithium Enolates ◽  
Enol Acetates ◽  
Radical Functionalization

It is shown that enolate ions, in particular lithium enolates obtained from enol acetates of saturated ketones by reaction with methyllithium, may not only be alkylated and carboxylated, but also alkoxycarbonylated (in position a to the original saturated keto group). By this method, saturated 20-keto steroids were transformed into 17α-methoxycarbonyl 20-ketones. Thus, from pregnenolone, 17-methoxycarbonylpregnenolone was prepared and was then converted to 17-hydroxymethylprogesterone and to some of its esters. This method for preparing 17-hydroxymethylated hormone analogues of the progesterone-corticoid group is simpler and more efficient than the pathway implying a free-radical functionalization of a 17α-methyl group.

A computational study of the 1,4-addition of lithium enolates to conjugated carbonyl compounds.

1991 ◽  
Vol 32 (6) ◽  
pp. 823-826 ◽  
Author(s):  
Anna Bernardi ◽  
Anna Maria Capelli ◽  
Angiolina Comotti ◽  
Cesare Gennari ◽  
Carlo Scolastico
Keyword(s):  
Carbonyl Compounds ◽  
Computational Study ◽  
Lithium Enolates

Silicon Assisted Sulfuration: Tetrachlorosilane-Sodium Sulfide-A New Potent Thionating Reagent for Carbonyl Compounds

2007 ◽  
Author(s):  
T. A. Salama ◽  
S. S. Elmorsy ◽  
A. M. Khalil ◽  
M. A. Ismail ◽  
A. S. El-Ahl
Keyword(s):  
Carbonyl Compounds ◽  
Sodium Sulfide

A FACILE SYNTHESIS AND REACTIONS OF AMINO SELENOLO[2,3-b]PYRIDINE CARBOXYLATE

2015 ◽  
Vol 12 (1) ◽  
pp. 3910-3918 ◽  
Author(s):  
Dr Remon M Zaki ◽  
Prof Adel M. Kamal El-Dean ◽  
Dr Nermin A Marzouk ◽  
Prof Jehan A Micky ◽  
Mrs Rasha H Ahmed
Keyword(s):  
Biological Activity ◽  
Carbonyl Compounds ◽  
Mass Spectra ◽  
The Other ◽  
Pyridine Derivatives ◽  
Facile Synthesis ◽  
High Biological Activity ◽  
Basic Hydrolysis ◽  
Pyridine Carboxylate ◽  
Hydrolysis Of

 Incorporating selenium metal bonded to the pyridine nucleus was achieved by the reaction of selenium metal with 2-chloropyridine carbonitrile 1 in the presence of sodium borohydride as reducing agent. The resulting non isolated selanyl sodium salt was subjected to react with various α-halogenated carbonyl compounds to afford the selenyl pyridine derivatives 3a-f  which compounds 3a-d underwent Thorpe-Ziegler cyclization to give 1-amino-2-substitutedselenolo[2,3-b]pyridine compounds 4a-d, while the other compounds 3e,f failed to be cyclized. Basic hydrolysis of amino selenolo[2,3-b]pyridine carboxylate 4a followed by decarboxylation furnished the corresponding amino selenolopyridine compound 6 which was used as a versatile precursor for synthesis of other heterocyclic compound 7-16. All the newly synthesized compounds were established by elemental and spectral analysis (IR, 1H NMR) in addition to mass spectra for some of them hoping these compounds afforded high biological activity.

Directed, Palladium(II)-Catalyzed Enantioselective anti-Carboboration of Alkenyl Carbonyl Compounds

2019 ◽  
Author(s):  
Zhen Liu ◽  
Xiaohan Li ◽  
Tian Zeng ◽  
Keary Engle
Keyword(s):  
Carbonyl Compounds ◽  
Building Blocks ◽  
New Method ◽  
Carbon Based

A substrate-directed enantioselective <i>anti</i>-carboboration reaction of alkenes has been developed, wherein a carbon based nucleophile and a boron moiety are installed across the C=C bond through a 5- or 6-membered palladacycle intermediate. The reaction is promoted by a palladium(II) catalyst and a mondentate oxzazoline ligand. A range of enantioenriched secondary alkylboronate products were obtained with moderate to high enantioselectivity that could be further upgraded by recrystallization. This work represents a new method to synthesize versatile and valuable alkylboronate building blocks. Building on an earlier mechanistic proposal by Peng, He, and Chen, a revised model is proposed to account for the stereoconvergent nature of this transformation.

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