Reduction of 3‐Acyl Derivatives of Oxindoles, Benzo[b]furan‐2‐ones, and Benzo[b]thiophen‐2‐ones to the Corresponding Alkyl Derivatives by Sodium Borohydride–Acetic Acid

Abstract

It was found that 3‐acyl derivatives of oxindoles, benzo[b]furan‐2‐ones, and benzo[b]thiophen‐2‐ones could be efficiently and conveniently reduced to the corresponding alkyl derivatives by pelletized sodium borohydride in acetic acid. A typical procedure involves heating the acylated substrates for approximately 90 min in a slurry of glacial acetic acid and sodium borohydride to provide the 3‐alkyl product in yields ranging from 62% to 96%. This synthetic methodology represents a convenient approach to the synthesis of the alkyl derivatives.

Keywords:

• Benzofuran‐2‐one
• benzothiophen‐2‐one
• borohydride
• oxindole
• reduction