Trifluoromethyl vinyl sulfide, a potential building block for pharmaceutically and agrochemically relevant products, is prepared and used for the first time in high-pressure-mediated 1,3-dipolar cycloaddition reactions with nitrones to synthesize (trifluoromethyl)sulfanyl isoxazolidines.

A new tandem strategy based on a Mannich/Pictet–Spengler sequence has been developed and applied to the synthesis of a new small library (14 examples) of privileged compounds based on the spiro[piperidine‐pyridoindole] core. The sequence proceeds by a diastereoselective Pictet–Spengler cyclization after condensation of several tryptamine derivatives with three novel piperidin‐4‐ones containing the fluorinated substituents F, CF3 and SF5. The piperidin‐4‐ones were synthesized from readily available starting materials by an enantioselective multi‐component organocatalytic Mannich reaction.

The advantages of performing reactions in continuous flow vs. the classic batch processes render flow chemistry a suitable technique for library synthesis. Inspired by our recent work to create fluorine‐containing nitrogen heterocycles and by the potential of the urea group in drug design, we herewith describe the combination of both aspects in the continuous flow synthesis of two libraries of urea derivatives based on the piperidin‐4‐one scaffold.