Hydrodediazoniation of Dry Arenediazonium<i>o</i>-Benzenedisulfonimides with Hydrogen Peroxide
作者:Stefano Dughera、Rita Fochi、Margherita Barbero、Iacopo Degani
DOI:10.1055/s-2004-831183
日期:——
electron-withdrawing substituents. Furthermore, it does not suffer from steric effects and always gives the pure reduction products 3 in excellent yields (15 examples, average yield = 93%). All the reactions show over 90% recovery of o-benzenedisulfonimide (4) that can be reused to prepare the salts 1. The collateral proofs we performed led us to hypothesize, for this reaction, a free-radical chain mechanism in which
Alkyl- and Arylthiodediazoniations of Dry Arenediazonium <i>o</i>-Benzenedisulfonimides. Efficient and Safe Modifications of the Stadler and Ziegler Reactions to Prepare Alkyl Aryl and Diaryl Sulfides
yields were obtained only when sterically hindered diazoniumsalts or thiols were used. A good amount of the o-benzenedisulfonimide (8) was always recovered from the reactions and could be reused to prepare salts 1. The copious experimental data collected in homogeneous conditions have offered several starting points for the study of the mechanism of these reactions.
A General Procedure to Selectively Prepare<i>N</i>-Alkylanilines by an Unexpected Reaction of (<i>Z</i>)-(<i>tert</i>-Butylsulfanyl)(aryl)diazenes with Alkyllithium Reagents
has been set up to prepare, selectively, the N-monoalkylanilines 7, reacting (Z)-(tert-butylsulfanyl)(aryl)diazenes 3 with alkyllithium 6 (MeLi, BuLi, s-BuLi, n-C 6 H 1 3 Li). The reactions were carried out in anhydrous diethyl ether at 0 °C or -78 °C, depending on the reagent 6, and then at room temperature. In optimal conditions the yields of the pure products 7 (uncontaminated by dialkylation products)
Arene and heteroarenediazonium o-benzenedisulfonimides can be used as efficient reagents in Sandmeyer cyanation. This work reports such reactions carried out by us under very mild conditions using tetrabutyl ammonium cyanide as a safe cyanide source and, interestingly, without the need for a Cu catalyst. The reactions have given rise to aryl nitriles in good yields (25 examples, average yield 75%)