Structural Effects in Radical Clocks and Mechanisms of Grignard Reagent Formation: Special Effect of a Phenyl Substituent in a Radical Clock when the Crossroads of Selectivity is at a Metal/Solution Interface
A chiral cyclohexadiene-based dihydrogen surrogate can distinguish between the enantiotopic faces of benzylic carbenium ions (see Scheme). No covalent interactions are required but instead dispersion controls the facial discrimination as verified by computations.