Preparation of Polyfunctional Arylmagnesium Reagents Bearing a Triazene Moiety. A New Carbazole Synthesis

[reaction: see text] The reaction of iodo- or bromo-substituted aryltriazenes with i-PrMgCl.LiCl generates the corresponding magnesiated derivatives which react with various electrophiles (acid chlorides, 3-iodoenones, allylic halides, aldehydes) affording polyfunctional triazenes. They can be readily converted to the corresponding polyfunctional aryl iodides. This new synthetic strategy was applied to prepare functionalized carbazoles.