Abstract Ozonolysis of N-acyl-2-(1-methylbut-2-enyl)-and N-acyl-2-(cyclopent-2-enyl) anilines followed by treatment with NaBH 4 afforded the corresponding 2-(2-hydroxyethyl-1- methyl) and 2-(1, 5-dihydroxypent-2-yl) derivatives. The reaction can be directed to indole derivatives by varying the nature of both the acyl group and reducing reagent.