The synthesis of epoxides is a useful reaction in organic chemistry, as it provides a good pathway towards trans‐diols through alkaline hydrolysis. Traditionally, this reaction is difficult to control due to its fast reaction rate and exothermic character. In batch, temperature runaway is largely overcome by controlled reagent addition and the use of milder epoxidation reagents such as metachloroperoxybenzoic acid (mCPBA), whose synthesis again requires the use of a peroxy compound and are less atom‐efficient. Epoxidation with peracetic acid poses its limits to batch scale‐up, but has been shown to be possible in continuous flow. The latter has the added advantage of handling all toxic and corrosive reagents inside a closed system.

Epoxidation and hydrolysis of model substrate
(R1 = H, acetyl; R2 = H, acetyl)

To avoid the use of expensive epoxidation reagents (e.g. mCPBA) while keeping a high throughput at the same time, FutureChemistry has translated this reaction from a batch process to a continuous flow process. FutureChemistry’s typical three‐tier approach led to a protocol which can be adapted to any viable alkene substrate:

      1) Translation of batch process to continuous flow process:
           a) Stock solutions approach, yielding a homogeneous reaction mixture.
           b) Quenching solution to follow the reaction in time.
           c) Flow markers approach to accurately assess reaction parameters.
      2) Automated reaction optimisation.
      3) Out scaling to preparative synthesis

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