Synthesis of β,β-Disubstituted Indanones via the Pd-Catalyzed Tandem Conjugate Addition/Cyclization Reaction of Arylboronic Acids with α,β-Unsaturated Esters.

Under Pd catalysis with a newly synthesized electron-deficient heterocycle, 2-(4,5-dihydroimidazol-2-yl)pyrimidine (as the ligand), the reaction of α,β-unsaturated esters with arylboronic acids afforded a wide range of 3,3-disubstituted indan-1-ones bearing a quaternary carbon in high yields. Mechanistic studies revealed that the reaction involves a tandem conjugate addition/1,4-Pd shift followed by a cyclization.