Cyclobutanes derived from the dimerization of cinnamic acids are the core scaffolds of many molecules with potentially interesting biological activities. By utilizing a powerful flow photochemistry platform developed in our laboratory, we have evaluated the effects of flow on the dimerization of a range of cinnamate substrates. During the course of the study we also identified a bis(thiourea) catalyst that facilitates better reactivity and moderate diastereoselectivity in the reaction. Overall, we show that carrying out the reaction in flow in the presence of the catalyst affords consistent formation of predictable cyclobutane diastereomers.

Cyclobutanes derived from the dimerization of cinnamic acids are the core scaffolds of many molecules with potentially interesting biological activities.Byutilizing apowerful flow photochemistry platform developed in our laboratory, we have evaluated the effects of flowo nt he dimerization of arange of cinnamate substrates.During the course of the study we also identified abis(thiourea) catalyst that facilitates better reactivity and moderate diastereoselectivity in the reaction. Overall, we showt hat carrying out the reaction in flow in the presence of the catalyst affords consistent formation of predictable cyclobutane diastereomers.

2 + 2] Photocycloaddition of Cinnamates in Flow and Development of a Thiourea Catalyst. -The bis(thiourea)-catalyzed dimerization of cinnamates (I) in a flow photoreactor gives rise to diaryl-cyclobutanedicarboxylates as a mixture of diastereomers (II) and (III). -(TELMESANI, R.; PARK, S. H.; LYNCH-COLAMETA, T.; BEELER*, A. B.; Angew.