Regioselective Synthesis of 3‐Substituted Pyrroles by Nucleophilic Addition of 3‐(1‐Arylsulfonylalkyl) Pyrroles Activated under Basic or Acid Conditions
Conditioned pyrroles! Sulfonylpyrroles, obtained regioselectively from commercial N‐triisopropylsilylpyrrole, undergo removal of the arylsulfonyl group under basic or acidic conditions to give vinylogous imino‐like derivatives (see scheme; TIPS=triisopropylsilyl). These electrophilic intermediates react with nucleophilic reagents to give 3‐functionalizedpyrroles.
AbstractThe reaction of sulfonylpyrroles with nitroalkanes in the presence of KF/alumina generates 3‐(2‐nitroalkyl)pyrroles in good yields. These compounds can be converted into trisubstituted 6‐azaindoles by a sequence of reactions comprising reduction of the nitro group, Pictet–Spengler cyclization and final oxidative aromatization.magnified image