The reaction of cyclopropenethiones and electron-deficient alkynes has been described in this context. The corresponding thioethers and thiocyclobutanones were afforded depending on the reaction conditions and the employed substrates. Ambient water participated in the reaction on the basis of deuterium labeling experiment. In the plausible reaction mechanism, we propose that the reaction might proceed through an autocatalytic process. (C) 2015 Elsevier Ltd. All rights reserved.