Controlled meta-Selective C-H Mono- and Di-Olefination of Mandelic Acid Derivatives.

Mandelic acids represent a key structural motif present in many drug molecules. Herein, we report the controlled meta-selective mono- and diolefination of mandelic acids by the careful design of the substrate and oxidant. Furthermore, free meta-functionalized mandelic acid was generated by selectively removing the template under mild basic conditions. The synthesis of functionalized homatropine and cyclandelate drug derivatives was demonstrated. Kinetic isotope effects revealed C-H activation as the rate-limiting step.