Continuous-Flow Preparation of γ‑Butyrolactone Scaffolds from Renewable Fumaric and Itaconic Acids under Photosensitized Conditions
2017-11-21T00:00:00Z (GMT) by
The method and results described herein concern the photosensitized addition of various alcohols to renewable platform fumaric and itaconic acids under scalable continuous-flow conditions in glass micro- and mesofluidic reactors. Alcohols were used both as reagents and as solvents, thus contributing to a reduced environmental footprint. Process parameters such as the temperature, light intensity, and the nature as well as amount of the photosensitizer were assessed under microfluidic conditions and, next, transposed to a lab-scale mesofluidic reactor connected with an in-line NMR spectrometer for real-time reaction monitoring. Substituted γ-butyrolactones, including spiro derivatives with unique structural features, were obtained with quantitative conversion of the starting materials and in 47–76% isolated yields. The model photoaddition of isopropanol to fumaric acid was next successfully transposed in a pilot-scale continuous-flow photoreactor to further demonstrate scalability.
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