Visible-Light-Promoted Metal-Free Three-Component Reaction for the Synthesis of Sulfonated 4-Amino-chromans, 4-Amino-tetrahydroquinolines, and 5-Amino-dihydrobenzo[ b ]oxepines

A visible-light-induced three-component sulfonylation/aminoalkylation of alkenes has been achieved to furnish a series of sulfonated 4-amino-chroman, 4-amino-tetrahydroquinoline, and 5-amino-dihydrobenzo[b]oxepine derivatives by using eosin Y as a photocatalyst. This metal-free synthesis strategy involves in situ imine condensation and visible-light-promoted C-S/C-C triple domino bond formation by using readily ortho-allyloxy-benzaldehydes, anilines, and sodium benzenesulfinates as substrates. This protocol features mild reaction conditions, broad substrate scopes, and good functional group compatibility, and they are therefore of potential practical value for the synthesis and structural modification of biologically active chroman derivatives.