The uncatalyzed addition of 2-trimethylsilyloxyfuran to (S)-(+)-2-(p-tolylsulfinyl)-1,4-benzoquinone 1 afforded a 3.4:1 ratio of the diastereomeric adducts 2:3. Acetonitrile was found to be the optimum solvent whilst the use of Lewis acid catalysts afforded lower overall yields.
