Direct palladium-catalyzed C-3 alkynylation of indoles
作者:Yonghong Gu、Xue-min Wang
DOI:10.1016/j.tetlet.2008.11.097
日期:2009.2
The direct palladium-catalyzed coupling reaction of indoles with alkynyl bromides was described in this paper. In the presence of catalytic amount of PdCl2(PPh3)2 and 2.0 equiv. NaOAc, the coupling reaction of indoles with alkynyl bromides proceeded smoothly at 50 °C to give the corresponding 3-alkynylindoles with high regioselectivity in good to excellent yields.
A chiral phosphoric acid catalyzed enantioselective [2 + 2] cycloaddition of alkynylindols or alkynylnaphthols with quinones is disclosed. A class of functionalized cyclobutenes with excellent yields, diastereo- and enantioselectivities were prepared under mild reaction conditions (70 examples, up to 99% yield, 99% ee, all > 50:1 dr). Mechanistic studies revealed that a dearomatization of indole or