Diastereodifferentiating [2+2] photocycloaddition of a chiral cyclohexenone with cyclopentene in supercritical carbon dioxide using a flow microreactor

The diastereodifferentiating [2+2] photocycloaddition of a chiral cyclohexenone with cyclopentene was performed in supercritical carbon dioxide (scCO₂) using a flow microreactor. In all cases examined, the microreactor gave higher conversions than the batch system because of the very short path length of the microreactor. Additionally, by using the microreactor, accurate temperature control produced higher diastereoselectivity. These distinguished findings can be attributed to the synergistic effect of superior light penetration in the microreactor and the unique solvent property (clustering effect) of scCO₂.