ChemInform Abstract: Aza-Wittig Reactions of Iminophosphoranes Derived from Ferrocenylazido Ketones: Preparation and Electrochemical Study of Novel Ferrocenyl-Substituted Azaheterocycles.

Abstract

Abstract α-Azidoacetylferrocene and 3-(o-azidophenyl)-1-ferrocenylpropenone have been prepared from acetylferrocene and they have proven to be useful building blocks for the synthesis of azaheterocycles. Thus, the three-component reaction of α-azidoacetylferrocene, isocyanates or acid chlorides and triphenylphosphine allows the direct formation of ferrocene-substituted oxazoles. Aza-Wittig reaction of the iminophosphorane derived from 3-(o-azidophenyl)-1-ferrocenylpropenone with isocyanates provides access to the corresponding carbodiimides which are cyclised either by the action of TBAF or amines to give ferrocenyl-substituted dihydroquinazoline derivatives. The bis(ferrocenyl)oxazole 13 showed in the cyclic voltammogram (†E 1 2 = 150 mV) moderate electronic coupling between the two ferrocenes through the oxazole ring.