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.