Synthesis of Spiro[indoline-3,2-pyrrolidine] Derivatives from (beta)-3-Indolyl Ketone Oximes

Spiro[indoline-3,2ʹ-pyrrolidine] derivatives were prepared from (beta)-3-indolyl ketone oximes by treatment with methanesulfonyl chloride and triethylamine via the bond formation between 3-position of the indole ring and oxime nitrogen. These diazaspirocycles were readily transformed to the corresponding spiro oxindole derivatives.