Visible-light photocatalytic difluoroalkylation in batch and flow via decarboxylation and 1, 2‑heteroarene migration

The introduction of fluorinated moieties into organic compounds has resulted in a dramatic enhancement of their physical, chemical, and biological properties, rendering medicinal and agrochemical compounds to be more potent. Benifiting from the flow technology, different stereoselectivity was observed between batch and flow experiments and exothermic reactions was realized in flow to allow for scaling up.
Visible-Light Photocatalytic Decarboxylation of α,β-Unsaturated Carboxylic Acids A simple yet effective photocatalytic decarboxylative protocol to prepare difluoromethylated styrenes and phenylacetylenes is described. By changing the reactor, having access to both stereoisomers is a unique and powerful approach and provides opportunities for other photocatalytic transformations. Compared with previously described methods, this procedure does not require additional metal catalysts or hypervalent iodine reagents to facilitate CO2 extrusion. The generality of our protocol is demonstrated by the broad substrate scope. Ortho-substituted cinnamic acids give the less stable Z-selective products. The thermodynamically favored E-stereoisomer could be readily obtained in continuous-flow through accurate control of the reaction time. Having access to both stereoisomers simply by changing the reactor is a unique and powerful approach and provides opportunities for other photocatalytic transformations. Visible-Light Photocatalytic Difluoroalkylation-Induced 1, 2 Heteroarene Migration of Allylic Alcohols A convenient method for the preparation of sp3 -rich heterocycles comprises a photocatalytic difluoroalkylation-induced 1,2-heteroarene migration of allylic alcohols. Here we describe for the first time the benefits of using flow to facilitate such migration reactions, including shorter reaction times, higher selectivities, and opportunities to scale the chemistry.