Highly palladium catalyzed chemoselective domino reaction: a practical way to the synthesis of 6H-benzo[c]chromenes and spiro[benzo[c]chromene-6,2′-chroman]s

Abstract A domino palladium-catalyzed hydrogenation reaction was developed to construct 6 H -benzo[ c ]chromene scaffold. Using Pd/C catalyst under H 2 balloon, 6 H -benzo[ c ]chromenes were obtained in nearly quantitative yields. However, using Pd(PhCN) 2 Cl 2 /DPEphos/AgBF 4 as the catalytic system, spiro[benzo[ c ]chromene-6,2′-chroman]s were obtained in up to 91% yields.