Aza-Wittig reaction of fluoroalkylated N-vinylic phosphazenes with carbonyl compounds. Usefulness of 2-azadienes for the preparation of fluoroalkyl pyridine derivatives
A method for the preparation of 3-fluoroalkyl substituted 2-aza-butadienes 6 by aza-Wittig reaction of 3-fluoroalkyl-N-vinylic phosphazenes 4 and aldehydes 5 is reported. [4+2] Cycloaddition reaction of these heterodienes 6 with enamines 9 gives fluoroalkyl substituted pyridine 15, 16, 24–27 and isoquinoline 12–14, 20 derivatives.
A method for the preparation of 3-fluoroalkyl substituted 2-aza-butadienes by aza-Wittig reaction of N-vinylic phosphazenes and aldehydes is reported. [4+2] Cycloaddition reaction with enamines affords fluoralkyl Substituted pyridine derivatives in a regioselective fashion. (C) 2004 Elsevier Ltd. All rights reserved.
Preparation of 3-(Fluoroalkyl)-2-azadienes and Its Application in the Synthesis of (Fluoroalkyl)isoquinoline and -pyridine Derivatives
作者:Francisco Palacios、Concepción Alonso、Marta Rodríguez、Eduardo Martínez de Marigorta、Gloria Rubiales
DOI:10.1002/ejoc.200400770
日期:2005.5
A method for the preparation of 3-(fluoroalkyl)-substituted 2-azabutadienes 5 by aza-Wittig reaction of N-vinylic 3-(fluoroalkyl)phosphazenes 4 and aldehydes is reported. Thermal 6π-electrocyclization of these azadienes gives 3-(fluoroalkyl)-substituted isoquinolines 6. Also [4+2] cycloaddition of these heterodienes 5 with enamine 8 gives fluoroalkyl-substituted pyridine derivatives 10–16. However,