2013 Volume 71 Issue 4 Pages 296-306
In the presence of catalytic amounts of copper salts, CuOAc or Cu(OAc)2, the reaction of arylboronic acids with electron-deficient alkynes proceeded in MeOH at ambient temperature to afford hydroarylation products with high chemo- and stereoselectivity. This method of synthesizing tri-substituted alkenes was further applied to the synthesis of biologically interesting molecules such as butenolides/pentenolides, 4-arylcoumarins, 3,3-diarylacrylonitriles, and 3-arylindole-2-carboxylates. Among them, the tandem hydroarylation/lactonization leading to 4-arylcoumarins is particularly fascinating as seven natural products were synthesized by the combination of three alkynoates and four boronic acids.
The copper-catalyzed conjugate addition was further extended to that of allylboronates as organoboron reagents. Thus, the copper-catalyzed conjugate allylation of various electron-deficient alkynes was achieved and the derivatization of the introduced allyl moiety was also investigated.
