Visible-light-mediated radical cascade reaction: synthesis of 3-bromocoumarins from alkynoates
作者:Shangbiao Feng、Jinlai Li、Zaimin Liu、Haiyu Sun、Hongliang Shi、Xiaolei Wang、Xingang Xie、Xuegong She
DOI:10.1039/c7ob02199b
日期:——
The development of a visible-light mediated bromo radical addition/spirocyclization/ester migration cascade reaction to generate 3-bromocoumarins from alkynoates is reported.
Anionic O → α- and β-Vinyl Carbamoyl Translocation of 2-(<i>O</i>-Carbamoyl) Stilbenes
作者:Mark A. Reed、Michelle T. Chang、Victor Snieckus
DOI:10.1021/ol049740t
日期:2004.7.1
[reaction: see text] New anionic oxygen to alpha- and beta-vinyl carbamoyl migration reactions, 17a and 26a-c --> 18 and 30a-c, proceed under LDA-mediated conditions leading stereoselectively to highly substituted stilbenes bearing electron-donating and -withdrawing substituents. Compounds 17a and 26a-c are prepared by combination of efficient, directedorthometalation, Sonogashira, and Suzuki-Miyaura
An expeditious and regioselective approach towards the construction of a spiro-chroman motif is described. Quinonemethides underwent a PTSA catalyzed annulation with 2-benzylidene dithiolanes to afford spiro-chroman dithiolanes in high yields. The synthetic versatility of the dithiolane motif was demonstrated by converting the adduct to coumarin, 3,4-dihydrocoumarin and chroman derivatives.