Montmorillonite K‐10 Clay Promoted Direct Dehydrative Nucleophilic Substitution of Pyrrole and Indole with 4‐Chromanols

Abstract A mild and inexpensive method of alkylation of pyrrole and indole with substituted 4chromanols and 3‐arylidene‐4‐chromanols mediated by montmorillonite K‐10 is reported. Indole and pyrrole upon treatment with 4‐chromanols in the presence of activated montmorillonite K‐10 undergo facile nucleophilic substitution under ambient condition to afford 2‐(chroman‐4‐yl)‐1H‐pyrrole and 3‐(chroman‐4‐yl)‐1H‐indole in moderate to good yields. In the case of 3‐arylidene‐4‐chromanols, this direct dehydrative substitution reaction is found to be highly regioselective affording only the respective C‐4 substituted (arylidene‐chroman‐4‐yl)‐ pyrrole/indole derivatives.