Late-Stage Diversification by Selectivity Switch in <i>meta</i>-C–H Activation: Evidence for Singlet Stabilization

Abstract

The full control of site selectivity in C–H activation is paramount for the programmed late-stage functionalization of structurally complex structures. During the past decade, directing groups have revolutionized molecular synthesis in terms of ortho-selective C–H activation. In sharp contrast, a selectivity switch that guides the typical ortho- to remote meta-C–H activation has thus far proven elusive. Herein, we describe the realization of such a concept for a robust selectivity control in ruthenium catalysis. The distal C–H transformation was guided by key mechanistic insights into the mild, synergistic action of carboxylates and phosphines in ruthenium(II) catalysis. Our findings allowed remote selectivity in broadly effective late-stage diversification of structurally complex drugs and natural product molecules, tolerating sensitive fluorescent dyes, drugs, lipids, peptides, nucleosides, and carbohydrates.