Studies using a homogeneous liquid flow photoreactor. Next, DCAS was tested under some initial photocatalytic flow conditions (Table ) in a commercial tubular coil continuous flow photoreactor (Vapourtec Ltd R-series/UV-150). Using 1a (12 mM) as our substrate and 5 mol% of DCAS at rt, a maximum yield of 25% for 2a (with 4:1 of 2a:3a selectivity) was obtained under recycling conditions (90 min) no matter whether dry air, O 2 , or (1:1) N 2 /O 2 were used (entry 2). The absence of catalyst (entry 2) or O 2 led to no reaction. Single pass conditions in the absence of LiClO 4 gave a similar yield (25%) and improved selectivity for 2a (entry 4, 2c was not detected). When the temperature was increased to 40 o C, the yield improved to 40% (entry 5). Under similar conditions but employing DCA as catalyst afforded 2a in 15% yield, confirming superiority of DCAS under flow conditions.