The reaction of indole with acetone in the presence of mineral/Lewis acid continues to be a fascinating area for investigation since 1913, specially due to the instability of the indolyl carbinol being generated in situ. We report here the synthesis of a novel spiro heterocyclic system obtained during the study of this reaction using BF3.Et2O.
Keywords: Indole, acetone, spiro system, X-ray crystallography