A novel method for synthesis of methylthio aryl ethynes was described, and eight compounds 1a～1h were obtained by the one-pot protocol starting from methylthiomethyl phenyl sulfone (MP-S) and aromatic aldehydes. The mechanism for the formation of 1 was discussed on the basis of trapping and characterization of some important intermediates. The results from experiments indicated that the reaction might involve the initial nucleophilic addition of MP-S to aromatic aldehyde to produce an intermediate 2 carrying two leaving groups, followed by double eliminations using lithium diisopropylamide (LDA) as base to form 1. This method is not only simple, but also does not require a tedious separation of the reaction mixtures because of less by-product.

Key words: double elimination, one-pot synthesis, methylthio aryl ethyne, methylthiomethyl phenyl sulfone, aromatic aldehyde