Photocatalytic Stereochemical Editing for the Concise Syntheses of (25S)‐Δ7‐Dafachronic acid, Demissidine and Smilagenin

Stereochemistry editing serves as an important tool to precisely adjust the desired stereochemical configuration of a molecule. In this study, enabled by photocatalytic stereochemical editing of tertiary C-H bonds of steroids, we have completed concise syntheses of (25S)-Δ7-dafachronic acid, demissidine, and smilagenin. The feasibility of regioselectively editing tertiary stereocenters with either very weak α-hydroxyl C-H bonds (in the synthesis of dafachronic acid), α-amino C-H bonds (in the synthesis of demissidine), or with varying steric hindrance (in the synthesis of smilagenin) has been successfully demonstrated.