Flow-photochemical synthesis of the functionalized benzobicyclo[3.2.1]octadiene skeleton

Technological Innovations in Photochemistry for Organic Synthesis: Flow Chemistry, High-Throughput Experimentation, Scale-up, and Photoelectrochemistry

Photoinduced chemical transformations have received in recent years a tremendous amount of attention, providing a plethora of opportunities to synthetic organic chemists. However, performing a photochemical transformation can be quite a challenge because of various issues related to the delivery of photons. These challenges have barred the widespread adoption of photochemical steps in the chemical industry. However, in the past decade, several technological innovations have led to more reproducible, selective, and scalable photoinduced reactions. Herein, we provide a comprehensive overview of these exciting technological advances, including flow chemistry, high-throughput experimentation, reactor design and scale-up, and the combination of photo- and electro-chemistry.

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

Due to their intrinsic physical properties, which includes being able to perform as volatile liquids at room and biological temperatures, fragrance ingredients/intermediates make ideal candidates for continuous-flow manufacturing. This review highlights the potential crossover between a multibillion dollar industry and the flourishing sub-field of flow chemistry evolving within the discipline of organic synthesis. This is illustrated through selected examples of industrially important transformations specific to the fragrances and flavours industry and by highlighting the advantages of conducting these transformations by using a flow approach. This review is designed to be a compendium of techniques and apparatus already published in the chemical and engineering literature which would constitute a known solution or inspiration for commonly encountered procedures in the manufacture of fragrance and flavour chemicals.

Benzobicyclo[3.2.1]octene Derivatives as a New Class of Cholinesterase Inhibitors

A library of amine, oxime, ether, epoxy and acyl derivatives of the benzobicyclo[3.2.1]octene were synthesized and evaluated as inhibitors of both human acetylcholinesterase (AChE) and butyrylcholinesterase (BChE). The majority of the tested compounds exhibited higher selectivity for BChE. Structural adjustment for AChE seems to have been achieved by acylation, and the furan ring opening of furo-benzobicyclo[3.2.1]octadiene results for compound 51 with the highest AChE affinity (IC₅₀ = 8.3 µM). Interestingly, its analogue, an oxime ether with a benzobicyclo[3.2.1]-skeleton, compound 32 was one of the most potent BChE inhibitors in this study (IC₅₀ = 31 µM), but not as potent as endo-43, an ether derivative of the benzobicyclo[3.2.1]octene with an additional phenyl substituent (IC₅₀ = 17 µM). Therefore, we identified several cholinesterase inhibitors with a potential for further development as potential drugs for the treatment of neurodegenerative diseases.

Flow Chemistry for Cycloaddition Reactions

Continuous flow reactors form part of a rapidly growing research area that has changed the way synthetic chemistry is performed not only in academia but also at the industrial level. This Review highlights the most recent advances in cycloaddition reactions performed in flow systems. Cycloadditions are atom-efficient transformations for the synthesis of carbo- and heterocycles, involved in the construction of challenging skeletons of complex molecules. The main advantages of translating these processes into flow include using intensified conditions, safer handling of hazardous reagents and gases, easy tuning of reaction conditions, and straightforward scaling up. These benefits are especially important in cycloadditions such as the copper(I)-catalyzed azide alkyne cycloaddition (CuAAC), Diels-Alder reaction, ozonolysis and [2+2] photocycloadditions. Some of these transformations are key reactions in the industrial synthesis of pharmaceuticals.