Green epoxidation of unactivated alkenes via the catalytic activation of hydrogen peroxide by 4-hydroxybenzaldehyde

An organocatalytic protocol that utilizes 4-hydroxybenzaldehyde as an activator of H 2 O 2 for the epoxidation of unactivated olefins is described. An unprecedented Payne/Dakin tandem mechanistic scenario is presented, supported by DI-HRMS experiments.