The oxidation of allylic systems has played a prominent role in this context as possibly the most widely applied C–H functionalization, owing to the utility of enones and allylic alcohols as versatile intermediates, and their prevalence in natural and unnatural materials. Despite many attempts to improve the efficiency and practicality of this transformation, the majority of conditions still use highly toxic reagents (based around toxic elements such as chromium or selenium) or expensive catalysts (such as palladium or rhodium). These requirements are problematic in industrial settings; currently, no scalable and sustainable solution to allylic oxidation exists. Here we describe an electrochemical C–H oxidation strategy that exhibits broad substrate scope, operational simplicity and high chemo selectivity. It uses inexpensive and readily available materials, and represents a scalable allylic C–H oxidation, enabling the adoption of this C–H oxidation strategy in large-scale industrial settings without substantial environmental impact.
Continuous processing has been claimed to enable a promising new business model that could radically improve quality control, decrease scale-up issues and cycle time, allow for faster release of new products, increase energy efficiency, reduce waste and process inventories, develop a safer process and provide better process control.
Asymchem has developed different types of equipment to support a wide range of reaction types and implemented processes on a wide range of scales. Recently, a continuous stirred tank reactor (CSTR) process was successfully developed for the continuous production of pharmaceutical intermediate, bearing the benefits in reduced solvent volume, low scale-up risk and improved yield.