Copper(I)-Catalyzed Regioselective Asymmetric Addition of 1,4-Pentadiene to Ketones.

By using commercially available 1,4-pentadiene as a pronucleophile, a copper(I)-catalyzed regioselective asymmetric allylation of ketones is achieved. A variety of chiral tertiary alcohols bearing a terminal ()-1,3-diene unit are generated in high ()/() ratio and high enantioselectivity. Both aromatic ketones and aliphatic ketones serve as suitable substrates. Furthermore, the reactions with ()-C(alkyl)-1,4-dienes proceed in moderate yields with acceptable enantioselectivity but with low (,)/others ratio, which demonstrates the partial isomerization of ()-allylcopper(I) species to ()-allylcopper(I) species through 1,3-migration. Subsequent Heck reaction and olefin metathesis compensate for the low efficiency with C-1,4-dienes. The synthetic utility of the product is further demonstrated by a copper(I)-catalyzed regioselective borylation of the 1,3-diene group.