Next Issue
Volume 9, June
Previous Issue
Volume 9, April
 
 
molecules-logo

Journal Browser

Journal Browser

Molecules, Volume 9, Issue 5 (May 2004) – 10 articles , Pages 264-382

  • Issues are regarded as officially published after their release is announced to the table of contents alert mailing list.
  • You may sign up for e-mail alerts to receive table of contents of newly released issues.
  • PDF is the official format for papers published in both, html and pdf forms. To view the papers in pdf format, click on the "PDF Full-text" link, and use the free Adobe Reader to open them.
Order results
Result details
Section
Select all
Export citation of selected articles as:
198 KiB  
Article
A Novel Strategy Towards the Asymmetric Synthesis of Orthogonally Funtionalised 2-N-Benzyl-N-α-methylbenzylamino- 5-carboxymethyl-cyclopentane-1-carboxylic acid.
by Narciso M. Garrido, Mohamed M. El Hammoumi, David Díez, Mercedes García and Julio G. Urones
Molecules 2004, 9(5), 373-382; https://doi.org/10.3390/90500373 - 30 Apr 2004
Cited by 8 | Viewed by 9800
Abstract
The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-α-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-α-methylbenzylamino-5–carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E)-octa-2,6- diendioate with lithium N-α-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid [...] Read more.
The asymmetric synthesis of the orthogonally funtionalised compounds tert-butyl 2-N-benzyl-N-α-methylbenzylamino-5-methoxycarbonylmethylcyclopentane- 1-carboxylate and methyl 2-N-benzyl-N-α-methylbenzylamino-5–carboxymethylcyclo- pentane-1-carboxylate by a domino reaction of tert-butyl methyl (E,E)-octa-2,6- diendioate with lithium N-α-methylbenzyl-N-benzylamide initiated by a Michael addition, subsequent 5-exo-trig intramolecular cyclisation and posterior selective hydrolysis with trifluoroacetic acid is reported. Full article
Show Figures

Figure 1

179 KiB  
Article
Nucleophilic Benzoylation Using a Mandelic Acid Dioxolanone as a Synthetic Equivalent of the Benzoyl Carbanion. Oxidative Decarboxylation of α-Hydroxyacids
by Gonzalo Blay, Isabel Fernández, Belén Monje and José R. Pedro
Molecules 2004, 9(5), 365-372; https://doi.org/10.3390/90500365 - 30 Apr 2004
Cited by 5 | Viewed by 8931
Abstract
The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation [...] Read more.
The synthesis of alkyl aryl ketones using a mandelic acid dioxolanone as a synthetic equivalent (Umpolung) of the benzoyl carbanion is reported. The methodology involves alkylation of the mandelic acid dioxolanone, hydrolysis of the dioxolanone moiety in the alkylated products and oxidative decarboxylation of the resulting α-hydroxyacids. The last step is carried out in a catalytic aerobic way using a Co (III) complex in the presence of pivalaldehyde under very mild conditions. Full article
Show Figures

Figure 1

219 KiB  
Article
Polymer-Supported Cinchona Alkaloid-Derived Ammonium Salts as Recoverable Phase-Transfer Catalysts for the Asymmetric Synthesis of α-Amino Acids
by Rafael Chinchilla, Patricia Mazón and Carmen Nájera
Molecules 2004, 9(5), 349-364; https://doi.org/10.3390/90500349 - 30 Apr 2004
Cited by 31 | Viewed by 10715
Abstract
Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethylene)glycine ester. [...] Read more.
Alkaloids such as cinchonidine, quinine and N-methylephedrine have been N-alkylated using polymeric benzyl halides or co-polymerized and then N-alkylated, thus affording a series of polymer-supported chiral ammonium salts which have been employed as phase-transfer catalysts in the asymmetric benzylation of an N-(diphenylmethylene)glycine ester. These new polymeric catalysts can be easily recovered by simple filtration after the reaction and reused. The best ee’s were achieved when Merrifield resin-anchored cinchonidinium ammonium salts were employed. Full article
Show Figures

Figure 1

235 KiB  
Article
Masked ω-Lithio Ester Enolates: Synthetic Applications
by Miguel Yus, Rosario Torregrosa and Isidro M. Pastor
Molecules 2004, 9(5), 330-348; https://doi.org/10.3390/90500330 - 30 Apr 2004
Cited by 11 | Viewed by 11320
Abstract
The protocol of lithiation by means of lithium and a catalytic (5% molar) amount of DTBB (4,4’-di-tert-butylbiphenyl), applied to ω-chloro ortho ester 6 under Barbier-type conditions gives, after final acid-catalyzed methanolysis, the corresponding functionalized esters 8 or 9 (for chlorotrimethylsilane as electrophile) or, [...] Read more.
The protocol of lithiation by means of lithium and a catalytic (5% molar) amount of DTBB (4,4’-di-tert-butylbiphenyl), applied to ω-chloro ortho ester 6 under Barbier-type conditions gives, after final acid-catalyzed methanolysis, the corresponding functionalized esters 8 or 9 (for chlorotrimethylsilane as electrophile) or, after ortho ester deprotection and acid catalyzed treatment, the δ-lactones 11. The procedure is also practical for bicyclic ortho esters 14: the β-chloro OBO ester derivate generates the γ- lactones 15 and the γ-chloro OBO ester gives corresponding esters 8. Full article
Show Figures

Figure 1

166 KiB  
Article
1-Hydroxymethyl-4-phenylsulfonybutadiene, a Versatile Building Block for the Synthesis of 2,3,4-Trisusbtituted Tetrahydrothiophenes
by David Díez, M. Templo Benéitez, Isidro S. Marcos, N. M. Garrido, P. Basabe and Julio G. Urones
Molecules 2004, 9(5), 323-329; https://doi.org/10.3390/90500323 - 30 Apr 2004
Cited by 3 | Viewed by 7775
Abstract
A method to synthesize chiral 2,3,4-trisusbtituted tetrahydrothiophenes in both enantiomerically pure forms starting from 1-hydroxymethyl-4-phenylsulfonylbutadiene is described. Full article
Show Figures

Figure 1

283 KiB  
Article
From Labdanes to Drimanes. Degradation of the Side Chain of Dihydrozamoranic Acid.
by Jesús M.L. Rodilla, D. Díez, J. G. Urones and Pedro M. Rocha
Molecules 2004, 9(5), 300-322; https://doi.org/10.3390/90500300 - 30 Apr 2004
Cited by 3 | Viewed by 9186
Abstract
A new route for the degradation of the saturated side chain of dihydrozamoranic acid has been devised, giving an advanced intermediate, compound 14, useful for the synthesis of insect antifeedants such as warburganal and polygodial. Full article
Show Figures

Figure 1

229 KiB  
Article
Synthesis of Highly Functionalised Enantiopure Bicyclo[3.2.1]- octane Systems from Carvone
by Antonio Abad, Consuelo Agulló, Ana C. Cuñat, Ignacio De Alfonso, Ismael Navarro and Noelia Vera
Molecules 2004, 9(5), 287-299; https://doi.org/10.3390/90500287 - 30 Apr 2004
Cited by 15 | Viewed by 11557
Abstract
The commercially available monoterpene carvone has been efficiently convertedinto the tricyclo[3.2.1.02.7]octane and bicyclo[3.2.1]octane systems characteristic of somebiologically active compounds. The sequence used for this transformation involves as keyfeatures an intramolecular Diels-Alder reaction of a 5-vinyl-1,3-cyclohexadiene and acyclopropane ring opening. Full article
Show Figures

Figure 1

268 KiB  
Article
Self-assembly of [2]Rotaxane Exploiting Reversible Pt(II)- Pyridine Coordinate Bonds
by Pablo Ballester, Magdalena Capó, Antoni Costa, Pere M. Deyà, Antoni Frontera and Rosa M. Gomila
Molecules 2004, 9(5), 278-286; https://doi.org/10.3390/90500278 - 30 Apr 2004
Cited by 8 | Viewed by 8015
Abstract
A dinuclear self-assembled cationic macrocycle based on Pt(II)-N(pyridine) coordinative bonds and having competitive triflate anions, as metal counterions, is used in the construction of [2]rotaxane and [2]pseudorotaxane architectures assisted by hydrogen bonding. The kinetic lability of the Pt(II)-N(pyridine) coordinative bond controls the dynamics [...] Read more.
A dinuclear self-assembled cationic macrocycle based on Pt(II)-N(pyridine) coordinative bonds and having competitive triflate anions, as metal counterions, is used in the construction of [2]rotaxane and [2]pseudorotaxane architectures assisted by hydrogen bonding. The kinetic lability of the Pt(II)-N(pyridine) coordinative bond controls the dynamics of the [2]rotaxane. Full article
Show Figures

Figure 1

205 KiB  
Article
Investigations into the Use of a Polyfluorooctanol as an Auxiliary Component for an Aldol Reaction
by Jason Eames and Hasina Khanom
Molecules 2004, 9(5), 266-277; https://doi.org/10.3390/90500266 - 30 Apr 2004
Cited by 4 | Viewed by 8176
Abstract
Results are reported on the efficiency of polyfluorooctanol as a perfluorousauxiliary component in the aldol reaction between the enolate derived frompolyfluorooctyl acetate and 2-fluorobenzaldehyde. Reduction of the correspondingpolyfluoro β-hydroxy ester with Super Hydride® gave the required 1,3-diol in good yield. Full article
Show Figures

Figure 1

126 KiB  
Editorial
Carbanion Chemistry from Carboxylic Acids: a Special Issue in Honor of Professor Ramón Mestres on his 65th Birthday.
by Margarita Parra and Salvador Gil
Molecules 2004, 9(5), 264-265; https://doi.org/10.3390/90500264 - 30 Apr 2004
Cited by 4 | Viewed by 5840
Abstract
This special issue of Molecules is to honour the 65th birthday of Professor Ramón Mestres.[...] Full article
Previous Issue
Next Issue
Back to TopTop