A Tandem Aldol-Diels-Alder Reaction Accelerated in Water: An Approach to the Catalyst-Free One-Pot Synthesis of Spiro Thio-Oxindoles

Spiro thio-oxindoles are prepared in situ by the reaction of the corresponding aldehydes and thio-oxindoles in a straightforward, environmentally friendly, highly efficient and simple procedure. The reaction took place in water with no catalyst added. This one-pot reaction afforded regio- and diastereoselective products in high yields (61-93%).