Pd(ii)–SDP-catalyzed enantioselective 5-exo-dig cyclization of γ-alkynoic acids: application to the synthesis of functionalized dihydofuran-2(3H)-ones containing a chiral quaternary carbon center
Pd(ii)–SDP-catalyzed enantioselective 5-exo-dig cyclization of γ-alkynoic acids: application to the synthesis of functionalized dihydofuran-2(3H)-ones containing a chiral quaternary carbon center
Enantioselective, Desymmetrizing Bromolactonization of Alkynes
作者:Michael Wilking、Christian Mück-Lichtenfeld、Constantin G. Daniliuc、Ulrich Hennecke
DOI:10.1021/ja402910d
日期:2013.6.5
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.