Synthesis of 2-Aminodihydrobenzofurans through Copper-Catalyzed N-Alkenylation/[3,3]-Rearrangement of Aryloxyamines with Alkenyl Boronic Acids

A variety of 2-amino-2,3-disubstituted dihydrobenzofurans were prepared in good yields and high diastereoselectivity through copper-catalyzed N-alkenylation and sequential [3,3]-rearrangement of aryloxyamines with alkenyl boronic acids under mild reaction conditions. Control experiments revealed that the monophosphine ligand played important roles in the C–N coupling reaction. More importantly, this N-alkenylation and [3,3]-rearrangement could be easily applied into the modification of natural products and drugs. The present method features the first example of a monophosphine ligand promoted Chan–Lam reaction and easy introduction of the dihydrobenzofuran core into complex molecules.