Rapid Production of trans ‐Cyclooctenes in Continuous Flow

A new method for rapid larger-scale production of trans-cyclooctenes (TCOs) in continuous flow was developed: Up to 2.2 g/h of specific TCOs can be produced by using this procedure. This method utilizes the classical photoisomerization of cis-cyclooctenes (CCOs) for the synthesis of TCOs but substitutes the conventionally used silver nitrate impregnated silica gel column for a liquid−liquid extraction module. In addition, this method provides the possibility of external addition of a substrate to scale up and speed up the production of TCOs because the concentration of the CCO is kept constant. This method was applied for the synthesis of several commonly used TCOs.