An efficient synthesis of hemiaminal of indoles by using tetrabutylammonium fluoride (TBAF) in water as a reusable reaction media

The synthesis of hemiaminal of indole is described by the reaction of indole with formaldehyde in the presence of TBAF in water at ambient temperature. The procedure is very efficient, mild, convenient, and environmentally benign with high yield of product. Moreover, the reuse of reaction media makes the procedure an attractive alternative to earlier methods.