Preparation of polyfunctional arylmagnesium reagents bearing a triazene moiety. A new carbazole synthesis

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