0000000000528244
AUTHOR
Fatemeh Mojarrad
Triazolopyridines. Part 11. Ylides derived from 2-Acylmethyltriazolopyridinium salts.
Abstract Ylides derived from 2-acylmethyltriazolopyridinium salts (2a) -(2c) react with methyl or ethyl propiolate and with dimethyl acetylenedicarboxylate to give ylides (3a)–(3e), (6) or (7). In some cases 1:2 adducts are formed, shown to be the novel ylides (8a)–(8d); an X-ray diffraction confirms structure (8a).
ChemInform Abstract: Organocatalytic anti-Selective Mannich Reactions with Fluorinated Aldimines: Synthesis of anti-γ-Fluoroalkyl-γ-amino Alcohols.
The asymmetric Mannich reaction between fluoroalkyl aldimines and aldehydes catalyzed by α,α-diphenylprolinol trimethylsilyl ether is reported. The corresponding Mannich adducts were reduced in situ to afford anti-β-alkyl-γ-fluoroalkyl-γ-amino alcohols in moderate yields and with very high diastereo- and enantioselectivities. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
Solution and fluorous phase synthesis of β,β-difluorinated 1-amino-1-cyclopentane carboxylic acid derivatives
An efficient protocol for the preparation of β,β-difluorinated 1-amino-1-cyclopentane carboxylic acid derivatives was developed. 2,2-Difluro-4-phenyl-3-butenoic acid 6 was used as substrate for the preparation of the starting vinyl difluoro imino esters 8. The key steps of this methodology rely on the chemo- and diastereoselective addition of allylzinc bromides over the iminic functionality of 8 and subsequent RCM reaction. This synthetic sequence was successfully applied to fluorous synthesis.
Nucleophilic substitutions on bromotriazolopyridines - an improved route to 2,6-disubstituted pyridines and to 1,3-disubstituted isoquinolines
Abstract A regiospecific synthesis of 2,6-disubstituted pyridines and of 1,3-disubstituted isoquinolines is described.
Organocatalyticanti-Selective Mannich Reactions with Fluorinated Aldimines: Synthesis ofanti-γ-Fluoroalkyl-γ-amino Alcohols
The asymmetric Mannich reaction between fluoroalkyl aldimines and aldehydes catalyzed by α,α-diphenylprolinol trimethylsilyl ether is reported. The corresponding Mannich adducts were reduced in situ to afford anti-β-alkyl-γ-fluoroalkyl-γ-amino alcohols in moderate yields and with very high diastereo- and enantioselectivities. (© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2009)
3-(2-Pyridyl)-[1,2,3]triazolo[1,5-a]pyridines. An experimental and theoretical (DFT) study of the ring-chain isomerization
An experimental (1H NMR) and theoretical (DFT) study of the ring-chain-ring isomerization of 3-(2-pyridyl)-[1,2,3]triazolo[1,5-a]pyrid-7-yl derivatives (A) into 6-{[1,2,3]triazolo[1,5-a]pyrid-3-yl}-2-pyridyl derivatives (B) has been carried out. Based on the calculations, a mechanism of several steps will be proposed. The experimental results as well as the calculations lead to the conclusion that the A-B ratio depends on the electronic properties of the substituents. © The Royal Society of Chemistry 2005.
ChemInform Abstract: Triazolopyridines. Part 11. Ylides Derived from 2- Acylmethyltriazolopyridinium Salts.
Abstract Ylides derived from 2-acylmethyltriazolopyridinium salts (2a) -(2c) react with methyl or ethyl propiolate and with dimethyl acetylenedicarboxylate to give ylides (3a)–(3e), (6) or (7). In some cases 1:2 adducts are formed, shown to be the novel ylides (8a)–(8d); an X-ray diffraction confirms structure (8a).
ChemInform Abstract: Solution and Fluorous Phase Synthesis of β,β-Difluorinated 1-Amino-1-cyclopentane Carboxylic Acid Derivatives.
An efficient protocol for the preparation of β,β-difluorinated 1-amino-1-cyclopentane carboxylic acid derivatives was developed. 2,2-Difluro-4-phenyl-3-butenoic acid 6 was used as substrate for the preparation of the starting vinyl difluoro imino esters 8. The key steps of this methodology rely on the chemo- and diastereoselective addition of allylzinc bromides over the iminic functionality of 8 and subsequent RCM reaction. This synthetic sequence was successfully applied to fluorous synthesis.