Journal of the American Chemical Society, Vol.135, No.22, 8133-8136, 2013
Enantioselective, Desymmetrizing Bromolactonization of Alkynes
Asymmetric bromolactonizations of alkynes are possible using a desymmetrization approach. The commercially available catalyst (DHQD)(2)PHAL promotes these cyclizations in combination with cheap NBS as a bromine source to give bromoenol lactones in high yield and with high enantioselectivity. The bromoenol lactone products, containing a tetrasubstituted alkene and a quaternary stereocenter are valuable building blocks for synthetic chemistry.