Alkenyl alane-pyridine complexes in a new synthesis of aryl alk-1-enyl sulfoxides

A new and an efficient synthesis of aryl alk-1-enyl sulfoxides is reported. The reaction between alane-pyridine complexes, triphenylphosphine, and sulfonyl chlorides affords the title products in good to excellent yields (70-94%) in short reaction times using mild conditions. The optimal ratio between reagents (alane-pyridine/PPh3/sulfonyl chloride 1.00/1.35/0.92) was obtained performing a chemiometric analysis. A rationale for the reaction was advanced.