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.