e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Journal of Organic Chemistry 2006-04-28
Single-isomer tetrasubstituted olefins from regioselective and stereospecific palladium-catalyzed coupling of beta-chloro-alpha-iodo-alpha,beta-unsaturated esters.
Alison B Lemay, Katarina S Vulic, William W Ogilvie
The efficient regioselective and stereospecific synthesis of tetrasubstituted olefins using a mild and convenient method is disclosed. 2-Alkynyl esters are selectively converted to E-beta-chloro-alpha-iodo-alpha,beta-unsaturated esters by exposure to Bu4NI in refluxing dichloroethane. These products are produced cleanly, regio- and stereoselectively, and in high yields. Single-isomer tetrasubstituted olefins bearing four different carbon substituents are then synthesized by sequential palladium-catalyzed coupling reactions. Selectivity results from reactivity differences in the intermediate substrates.