Iodine-promoted oxidative homocoupling of methyl 2-arylacetates under equilibrium conditions using potassium tert-butoxide as a base

Iodine-promoted dimerization of enolates of methyl 2-arylacetates generated with tBuOK under equilibrium conditions are reported. The oxidative homocoupling reaction furnishes a mixture of dl and meso dimers in moderate to good yields and diastereoselectivity. Electron-withdrawing substituents on the aryl ring seem to facilitate dimerization leading to higher yields and ortho-substituted aryl acetates afford better diastereoselectivity.