Electrochemical Ferrier rearrangement of glycals in flow

The Ferrier rearrangement is a cornerstone transformation in carbohydrate chemistry, typically requiring strongly acidic or oxidative conditions. Here we report a continuous-flow electrochemical Ferrier rearrangement operating in an undivided microreactor equipped with inexpensive graphite electrodes mitigating batch process limitations, such as insufficient mass transfer and charge utilization. The process proceeds efficiently with minimal supporting electrolyte and charge input, converting a wide range of acyloxy- and alkoxyglycals with diverse oxygen-, sulfur-, nitrogen-, and carbon-based nucleophiles to 2,3-unsaturated glycosides in up to 94% yield and excellent diastereoselectivity. The short interelectrode distance enables completion under 20 seconds residence time, affording gram-scale productivity (10 mmol·h^-1) and high faradaic efficiency. Mechanistic and electrochemical data support a radical-chain pathway initiated by anodic oxidation of glycal. This operationally simple and scalable protocol advances electrochemical glycosylation toward sustainable, industry-relevant synthesis.