Reductive Heck cyclization versus δ-carbon elimination/decarboxylation: synthesis of dihydroindole and indoles from Baylis-Hillman adducts

Modified Baylis-Hillman adducts having 2-bromoaniline moiety at the primary position underwent Pd-mediated reductive Heck type cyclization to produce dihydroindole derivatives. The same starting materials can also be used for the synthesis of indole derivatives under slightly different conditions via the concomitant δ-carbon elimination and decarboxylation process.