Synthesis of 2,3-Dihydrobenzofuran by Tandem Palladium-Catalyzed Reactions

Significance

The synthesis of 3,3-disubstituted 2,3-dihydrobenzofurans by two Heck or Heck-Suzuki cross-coupling sequential reactions is reported. Starting from simple reagents, three types of benzofuran derivatives are obtained by hydride capture (formic acid as hydride source), double Heck, and Heck-Suzuki or Stille cross-coupling reactions. The scope in the Heck-Suzuki process was reasonably well explored in terms of aryl­boronic acids bearing EWGs and EDGs; however, structural variation in starting phenol was not investigated. In the double Heck reaction, the same product was also obtained in a one-pot process but in reduced yield.