Photochromic Oxime Directing Groups for Spatially Controlled Pd-Catalyzed C–H Difunctionalization with Tandem Electrophiles

Herein, we report the employment of oxime ethers as photochromic directing groups for the controlled functionalization of spatially and inherently distinct C(sp2)–H/C(sp3)–H bonds. Our approach features a semi-two-pot protocol for Pd-catalyzed C(sp2)–H oxygenation, photoisomerization, and Pd-catalyzed C(sp3)–H arylation for the synthesis of difunctionalized oxime derivatives in a highly selective and controlled manner. Notably, we illustrate the rare utilization of hypervalent iodine reagents as tandem electrophiles for C–H difunctionalization. The reverse sequence of functionalization events can be achieved thermally, thereby providing a platform for full directing group-controlled C–H difunctionalization. Overall, this work highlights that photochromic directing groups can provide an avenue for positionally controlled C–H difunctionalization.