Cobalt?Catalyzed Cyclization of N?Methoxy Benzamides with Alkynes using an Internal Oxidant through C?H/N?O Bond Activation

Abstract

The cyclization of substituted N?methoxy benzamides with alkynes in the presence of an easily affordable cobalt complex and NaOAc provides isoquinolone derivatives in good to excellent yields. The cyclization reaction is compatible with a range of functional group?substituted benzamides, as well as ester? and alcohol?substituted alkynes. The cobalt complex [CoIIICp*(OR)2] (R=Me or Ac) serves as an efficient catalyst for the cyclization reaction. Later, isoquinolone derivatives were converted into 1?chloro and 1?bromo substituted isoquinoline derivatives in excellent yields in the presence of POCl3 or PBr3.