α‐Thianthrenium Carbonyl Species: The Equivalent of an α‐Carbonyl Carbocation

Here we report an α‐thianthrenium carbonyl species, as the equivalent of an α‐carbonyl carbocation, which is generated by the radical conjugate addition of a trifluoromethyl thianthrenium salt to Michael acceptors. The reactivity allows for the synthesis of C(α)‐tetrasubstituted α‐ and β‐amino acid analogues via a Ritter reaction by addition of acetonitrile. Addition of hydroxide, methoxide, and even fluoride can afford α‐heteroatom substituted α‐phenylpropanoates.